High Flow + High Co2 = Algae?! What?!

[Rorie]

Here are some photos to help. You can see the main algae growth is on the rocks. With BGA only on the moss on my wood.....right in front of the powerhead!

Ok, so photo 1 you can see the new grass which i have just planted to try out. It is GREEN, where as the existing grass looks nearer brown

Image two and 3 you can see my whole tank. Top back wall has the two spray bars aiming at the bottom of the front wall. The two pumps are on the side walls, half way down, with the idea that they will push the ferts and CO2 down to the substrate.

Image 4 is of the BGA on the moss

The final photo is of the moss all over the rocks

Hope this helps!

My third pump turned up today, so if needed, please give suggestions as to where to put it!

 

[SuperColey1]

Here are some photos to help. You can see the main algae growth is on the rocks. With BGA only on the moss on my wood.....right in front of the powerhead!

Ok, so photo 1 you can see the new grass which i have just planted to try out. It is GREEN, where as the existing grass looks nearer brown

Image two and 3 you can see my whole tank. Top back wall has the two spray bars aiming at the bottom of the front wall. The two pumps are on the side walls, half way down, with the idea that they will push the ferts and CO2 down to the substrate.

Image 4 is of the BGA on the moss

The final photo is of the moss all over the rocks

Hope this helps!

My third pump turned up today, so if needed, please give suggestions as to where to put it!

Diagram below to explain.
Firstly there is no need to 'point' a spraybar downwards. If you spray water at a wall at velocity it hits the wall and goes in all directions outward. In water the effect is s bit less and most goes downward. So you point it at the front glass directly (or just down a bit) and some moves upward and gives you the ripple and the rest goes downward, then along the bottom back to the intake.

This is the same as using a lily pipe or jet pipe etc and the reason ahy diffusers are placed opposite the flow. the water runs along the tank, hits the glass and is forced down where it meets the rising bubbles and forces them back down too.

The reason inline CO2 works better with a single outlet is because the velocity at that single outlet is much higher than the spread out velocity of the spraybar. Also because the flow is greater (if indeed the spraybar does restrict flow)

I will do a test tomorrow with my old tetratec with and without the spraybar. see what (if any) difference there is.

The spraybar should be an inch or so under the surface of the water. Same with a lily or jet pipe. The connection before the spraybar can be used as a jet pipe in essence.

I've put 2 powerheads pointing from the front corners towards the centre of the tank (not the substrate to the dead centre i.e. half way front to back, half way left to right and half way up and down. Like X wing fighters pointing their lasers at the heart of the death star.

The other one I have pointed at an angle to the substrate. Not how it SHOULD be set up because there is no 'should'. Only you can work that one out form how your tank flow is. Plants, hardscape etc are different in all tanks and they greatly affect where the water goes in terms of flow.

I would just try the filter without the spray attached. No need to buy a lily pipe. Then utilise the powerheads to 'boost' the circulation. you don#'t want conflicts or you just end up wasting them. They should compliment the flow rather than compromise it.

Andy

 

[Rorie]

I will change my set up tonight and see how i get one with that. The filter output which has the CO2 difused in it comes from one side, to half way. then the second filter output (with no CO2) comes from the other side to half way. So i am not sure if putting my pumps pointing to the middle will have a good effect? It would seem that the CO2 would only get circulated in half of the tank?

Do you think my third powerhead would be of use?

Other question - if i am pushing the flow into the middle of the tank, how will the substrate get folw? If the flow hits the front glass, travels down and round (towards the back) should i have the powerheads on the back, low down, aiming up to the middle?

RE the spray bar, i am not sure i agree with your theory. A flow through a pipe will increase if the diameter of the pipe decreases (think of putting your thumb over the end of a hose pipe). So having several small holes (spray bar) rather than one big one will mean higher flow. Provided the cumlitive diameter of the spray bar holes is less than the pipe size.

The only way this would not be true is if the powerhead in the filter was so weak that with some restriction (due to smaller pipe/holes)would slow it down, hence, slowing the flow.

However, i dare to contradict the proven results, so your test will be interesting to see!

 

[SuperColey1]

If the spraybar points to the glass, then pushes down then along the bottom then putting the powerheads at the bottom pointing to th middle s n effet tryig to psh e flow back fom where itcame from


[/quote]RE the spray bar, i am not sure i agree with your theory. A flow through a pipe will increase if the diameter of the pipe decreases (think of putting your thumb over the end of a hose pipe). So having several small holes (spray bar) rather than one big one will mean higher flow. Provided the cumlitive diameter of the spray bar holes is less than the pipe size.[/quote]

Nice hosepipe anaolgy however it is flawed. Take your hosepipe and turn the tap on full. Say 2 litres a minute is coming out. Looks like a trickle. Put your thumb over the end and it looks more powerful the spray goes further. thats because the pressure is trying to push all that water through that reduced space. It doesn't all get through though.

Take another analogy

Fill up a waterbed so it is full. Then get a pin and pierce it. A tiny jet of water comes firing out. fast enough to take your eye out.
Get another bed fill it up the same amount. Take a knife and put a slit in it. The water will empty within seconds but it will pour out.

This is what I mean r.e. the spraybar. It may come out faster and look more powerful but unless the total are of those holes matches the total area of the hose end (or connector) then it will come out with more force but not the same volume. Hence restricting flow, hence the filter taking in less water because it is pushing out less water.

I'll do the test but probs tomorrow now. Virgin superhub arrived and I need to set it up, the send out shrimp, then get the kids. lol You know the score.

The pump will always be capable of pumping more than it does. media will slow most externals down by up to 50%. Sometimes more. The pump can only pull in what it can expel though and if it struggles to get 1200lph out of the outlet then it won't draw in 1200lph either.

It was just something I read that I'd never though about before but will test it before I go as far as to say it is true

The Tetratec will be a good example to use too as if anything can reduce flow at the slightest problem its a Tetratec. Hence its position in the cupboard as a last minute backup

Andy

 

[fivecheebs]

Im not going to get involved over the cause of the algae, as I am far too green at this to comment with confidence. However, I can go into some detail on how pumps work, and how restrictions effect flow. (sorry to go off topic slightly, but it could be interesting for some)

As Andy said Rorie, you are confusing flow, with velocity. Flow describes the quantity of water, velocity describes the speed of the water. Its easily possible to have more velocity, but less flow, just like your hosepipe analogy.

Andy, (excuse me if i am preaching to the choir, this is for others benefit also) your point about the spraybar decreasing flow is possible, but depends on a multitude of variables. As you say, if the total sum of the area of the output of the spray bar is less than the area of the single outlet, it could cause a flow restriction. Also to be considered, is how the spraybar attaches to the output. If it connects with an elbow, then that will further restrict flow compared to a lilly pipe, for example, which has less extreme corners.

Disregarding the way the spraybar connects to the output, if the area of the outputs from the spraybar is greater than the the area of the single output, flow will not decrease, but it wont increase either as that is already limited by what is before the output.

Now here comes the complicated but about the pumps. All pumps are different. You will have heard of "head rating" or "lifting height" when looking at the specs of pumps. This can be interpreted as the pumps ability to push past a restriction. the higher the rating, the less impact a restriction will have on the flow. We don't actually lift any water with our external filters, as essentially we have what is known as a "closed loop". The gravity that feeds the filter, also pushes the water back up the outlet (just like if you started off a siphon, and then lifted the lower part of the tube above the water level - flow stops, and the water levels settle at the same height), the pump merely pushes water around the loop. You could compare the flow of your filter with single and multiple outputs, and you might find that the difference is negligible. Another person can perform exactly the same test and find completely the opposite due to the characteristics of his pump.

The pump can only pull in what it can expel though and if it struggles to get 1200lph out of the outlet then it won't draw in 1200lph either.

What you say is completely correct. the loop is closed, so any restriction is detrimental to performance, but magnitude of that hit on performance depends on where the restriction is in relation to the pump. The performance of a pump is greatly reduced by a restriction at the inlet. Pumps are really bad at "pulling" water, but are great at pushing it. Going back to the hosepipe analogy, lets imagine a siphon. for arguments sake, lets say the siphon is operating over a large height. put your finger over the end of the hosepipe where all the water is exiting, and the same thing happens as it did earlier. flow is reduced a little, but velocity is greatly increased. Now move your finger to the other end of that hose... you will likely find that the velocity has reduced marginally and flow is significantly reduced. The reason is that the pressure at the top of the siphon is much less than the pressure at the bottom. Now reduce the height of the siphon, but put a pump inline. The effect is the same.

 

[Rorie]

haha, theory = practice aint always the case.

V^2/2+gz+p/ro=constant - the equation for incompressible flow......theoretical obviously, but the basis of my argument, assuming pipes will not expand and your filters power head will operate at a CONSTANT speed producing the same flow of fluid

If we look at the basic principal of fluid dynamics, Bernoulli's law. That would go with what i was saying - provided the output from the filter box is constant (assuming the power head will not reduce in power), then the output WILL be the same. The velocity at what it expels (from lily pipe/spray bar/ what every) is the variable.

The example of the water bed is valid, but this has a different variable. The bed will move to accommodate your weight as it is flexible. the only way this is relivent is if your system (piping etc) will change shape and expand

SO, if what you are saying is correct - with a single out put rather than a spray bar - there are various things which could change the result. From the pump under performing due to the pressure of the water in front of it (as it 'struggles' out of the spray bar), to expansion of hose pipes to accommodate the backlog of pressure (similar to your water bed theory).

Sorry, but gonna agree to disagree here. Not as black and white as you are looking at it. It has been a couple years since i have studies Fluid dynamics, hydraulics etc, but i have done so at a high level

But back to the algae

 

[SuperColey1]

Its been proven many a time about flow reductions. Just add an extra bend in the line and it's reduced, ad an inline item and its reduced so its not a case of xlph powerhead will always push x amount out of the outlet. Yes there is back pressure. But it is very well known that a filter with 700lph powerhead will not have a turnover of 700lph unless it is empty and has very short hoses. That is already fact!!! It may constantly be trying to 700lph through it but that does not mean it is able to achieve it even with it running at exactly the same level. The variables DO decide how much that powerhead can pull through it.

Anyways. don't want to argue. every one seems to want to argue with me at the mo, many because they don't read my posts and cannot understand what I am saying (this isn't the case with you ) and I'm close to not bothering with the forums again.

Maybe it is due to the number of people scanning as quick as poss without bothering to try and understand. I think people should put their internet phones down and read things properly when they have enough time to do so rather than quick scans followed by premature frantic keying!!!

I'll just do the test tomorrow (if I have time after the baby scan) and post up the results. If not tomorrow sometime over the weekend.

 

[Rorie]

easy tiger, i am not arguing with you! A disagreement, or discussion is not an argument! If i said "YOU ARE WRONG, SHUT UP" then maybe haha, but its not the case, please dont take it that way.

I 100% agree that with bends, increase height, media in the filter etc will reduce your output. This is the limitations of your power head. If it has infinite power and torque, then that would not be the case - the flow rate wouldnt be effected.

As i said, the theory is theory!! There are to many unknowns in the system to say 'It will' or 'it will not' effect the flow.

Forums are interesting places. I come on for advice when i have a problem (like my darn algae!), and am extremely grateful for people like yourself who give detailed and reliable answers! So thank you again! (granted my problem has not gone yet, so dont run away ;P

BUT, there are always those who try to stir things up, tell you that you are wrong etc. I fishless cycled my PLANTED tank. Some people told me i was wrong, it wouldnt work etc etc etc. But for me, i understood and monitored what i was doing. The test results acted as i predicted, all went well, and i added 50 cardinal tetras and 4 bolivian rams and soon after discus, and did not have a single problem! Point and case - everybody has an opinion, but they are not always right! Take it with a pinch of salt, and do what works for you!

Now, back to the algae

Last night i shortened my spray bar (sorry to say it) to increase the force of the flow coming out (huge difference) and its now hitting the front wall of the aquarium. I could see some rubbish move in the pattern i wanted it to, so thats great. But this means the CO2 is only getting added at one end of my tank. So i have the power head at the front of the side pane of glass, aiming towards the middle. I did the same with the output on the other side of the tank with a second power head. This has the flow moving (hopefully) in the correct way. The only issue now is that the CO2 is not circulating the whole tank.

What do you think?

ooh, and baby scan....congrats!

 

[SuperColey1]

What do you think?

I think you will have reduced the throughput but increased the speed of the flow for the lower throughput. however I'm not saying any more on that till I've tested it (apart from this final paragraph or 2 .) As I said at the beginning it was only from a discussion I was reading on another forum earlier this week that I thought about it. Never really considered spraybar adding to the reduction before however many people like yourself who state (yanyone can state so I don't know how truthful they were being) that they have an 'extended knowledge' of fluid dynamics saying the opposite to yourself.

In fact throughput from an Eheim versus Tetratec same rated filter put the Eheim ahead by a margin of the Tetratec. The Tetratec only giving out 48 or so % of the maximum turnover while the Eheim gave out mid 50's. I don't see why if other variables reduce flow such as bends, kinks, height etc then why a spraybar with smaller total area of exit than the pipe diameter would not act in the same way as a kink?

I'm not saying you are arguin with me (although you are. lol) its just that I write things and these days I will even put at the beginning a sort of disclaimer stating that I am generalising or that I am theorising however people don't read things properly. they read the statement as quickly as they can, don't associate the 'disclaimer' and the get all bolshy with me. Last night there were several and is one reason I disappear from forums for months at a time. Because I get tired of these sort of people who can't read the whole thing, weigh up it's merits for what they are and then get upset because of their interpreatation of something they haven't read peoperly.

Like I said in the last post. I don't mean you. You are debating based on your understandings and even though I think you're wrong I can accept that and without testing I can't really say or suggest that you are wrong otherwise I become as bad as those who just recycle garbage about N&P meaning algae because they read it somewhere or were told by someone

ooh, and baby scan....congrats!

Many thanks

I'm sure sorting flow will sort out the CO2 and EI WILl sort out the nutrient and then you are 90% of the way to success.

On the 'fishless cycle in a planted tank how did you get readings? Not many plants? where was the ammonia coming from and why weren't the plants using it up?

When we say that a planted tank WON't cycle that is a generalisation based on a 'planted tank' being very heavily planted. That is a little dangerous because in many eyes (including mine) 1 plant in a tank makes it a 'planted tank' and therefore that 'planted tank' will definately cycle. Maybe something that we need to add to anything where we state this. The definition of a 'planted tank' in context with the article that is being discussed but then people would scroll past this definition, scan the main info and then moan about dead fish. Its a problem with the modern world that everyone's time is far to precious to do things properly, research properly, read and think. They search, scan the result and put it into action without using any more effort (if you can call it effort) than they possibly need to.

That's my main gripe. I have algae free tanks, I can run a hi tec CO2 setup with ease, I can run highlight over non CO2 tanks without a problem. I can buy a tank and put fish in it within hours without fear of it cycling or new tank syndrome nor have to do any waterchanges ever. But then I am always reading, thinking, testing, sometimes even accidentally finding I've done something that sorts a problem or makes things easier. I want to learn continually. May sound funny from a high school leaver that has not worked for 3 years but I want to learn. I want to progress and I want to correct any misunderstandings or incorrect knowledge that I have. No problem with me accepting if I am wrong because that means I have replaced incorrect data in my brain cell (<----singular. lol) with correct data.

EDIT Lost myself a little and wrote 5 paragraphs bemoaning other doleites wasting their time watching TV and playing on games consoles when they should have matured past playing computer games. lol I've deleted all that out

I'm off to the baby scan then going to get the filter setup next to some water butts. Going to do several tests that should be good reading. I'll put that in a different thread cos I've ruined this one with moaning about how modern society is so disappointing. lol

AC

 

[SuperColey1]

Wel....the plan to use the old Tetratec didn't pan out. Can't find the hose connector piece to fit into the top of the powrhead. Probs threw it out. lol

Sooo.... I used my current Eheim 2224. Same turnover @ 700lph as the Tetratec EX700 was.

The test was setup as follows:

The current inlet remained in the tank. This ensures there isn't any airlock or difference in the filter's water content. The outlet was then directed into a 20 litre bucket set at the same height as it would be for the outlet 'crook' to go over the aquarium glass.

The filter has the complete set of recommended media in it plus a bag of Purigen so it is full to capacity inside. The hose length is 1 metre from powerhead to inlet/outlet attachment. The outlet also has an inline heater. There will be reduction in flow due to these factors.


These aren't going to be super accurate measurements however they do give and idea.

Test 1 - Outlet = Glass Lily pipe = Throughput in 2 minutes = 12.1 litres
Test 2 - Outelt = Tetratec 'crook' without spraybar. Throughput in 2 minutes = 12.4 litres
Test 3 - Outlet - Tetratec 'crook' with spraybar. Throughput in 2 minutes = 11.8 litres

Thes 3 measurement seem very close however they do show a difference.

It means that using:
The Lily pipe the filter turnover is 363lph (52% of 700lph)
The Tetratec 'crook' without attaching the spraybar the filter turnover is 372lph (53%)
The Tetratec 'crook' with spraybar attached the filter turnover is 354lph (51%)

I would expect these figures to be much lower and maybe a larger difference because from past tests (not done by me) and my own experiences the Eheim rated the same as the Tetratec is much better at maintaining flow.

So from the tests above The outlet on it's own came out top as I expected. This is probably because the whole hose diameter is being used and therefore no restrictions ahead of it. If the used a typical smooth bend 'crook' instead of the angular square one their 'research & design' team decided on I would expect it to be even higher.

The Lily pipe is slightly less than the outlet on it's own. I would suggest this is because the Lily pipe restricts the flow a little as it's outer diameter has to fit into the inner diameter of the hose thus a narrower internal measurement of the Lily pipe. However I suspect some of the restriction is negated because it has a traditional smooth bend and therefore less turbulence than the Tetratec 'crook'. Against the traditional 'crook' it would be a larger difference.

The spraybar as I suggested above does reduce the flow. Not a huge amount but it is still there. The spraybar was the full 2 piece one supplied with the Tetratec EX700 and it was used in conjunction with 'crook' it was supplied with.

Conclusions:
Tetratec's aren't very good I knew that a long time ago hence why I grudgingly paid out for an Eheim.
Spraybar's DO reduce the flow no matter how small the difference/
An outlet without spraybar has less restriction than a Lily pipe.

Andy

 

[Rorie]

I'm not going to upset you again, but you cannot conclude like that!

As i stated before, the only way the spray bar will create a reduction in flow is if something else changes....and again, i will point out that the most likely cause will be an inefficiency of your powerhead to keep the flow constant.

Your experiment may have proved that a spray bar gives reduced flow (although there are still to many variables in you wee experiment such as reduced water head in your tank, increase in pipe length etc etc) but the reason for this is above, or potentially something else, or of course a combination of many things. AS I STATED.

If you had a good powerhead (maybe the Eheim would make a difference) that did not reduce in power when given a restriction, then the results would even out.

You also cannot conclude that 'spray bars' are the blame for your reduced power. It would all depend on the cumulative size of the holes compared to that of the pipe you were using. My spray bar had three standard Eheim sections added together. The cumulative area of holes was greater than that of the pipe....... so there is no reduction in flow, but a reduction in velocity. FACT. I used it to even out the distribution of filtered water entering my tank.

Bernoulli found this out in 1738..... I am, as all engineers would, more likely to be trusting in his experiments i'm afraid.

many people like yourself who state (yanyone can state so I don't know how truthful they were being) that they have an 'extended knowledge' of fluid dynamics

Having a Masters degree in Civil and Structural Engineering and years of experience in the industry, I, my Universtiy, the Institute and my company would expect my knowledge to be reputable. I have also just issued reports proving that a large, global company's testing procedures are flawed which is currently causing trouble for a lot of people. So don't even get me started

Forums are a good bank of knowledge, but also great for rubbing people up the wrong way for so many reasons! as i stated before, i think we should agree to disagree on this. I have my knowledge on the subject, you have yours. You maybe dont agree with mine, but i dont agree with yours.
I still have algae! haha

 

[SuperColey1]

Ok we'll disagree BUT I should point out it was the Eheim powerhead and the only variable was the outlet. each outlet onto the same outlet hose. The inlet stayed the same. water was returned to the tank after each test so was the same amount of water etc.

Anyways. doesn't really matter.

p.s. this is the thread that got me thinking last week. Does have someone on there talking about flow dynamics and funnily uses a hose pipe analogy. lol. thy however use it the same way as I did.
http://www.aquascapingworld.com/forum/equipment/169-how-come-amano-doesnt-use-spray-bar-2.html


and....I still don't have algae! haha

But keep on and you won't either. we are sorting things out one at a time and therefore eahc change needs time to take efect (or not as the case may sometimes be). After we eliinate each thing we can move to the next etc until we get there

Andy