Blending water... Hard & thru whole house Softener & RO... what to expect???

1st off... a big thank you to all those who have responded to my water chemistry questions... I'm really not that dense... but I do like to fully understand the what's? & whys?... I think I finally have gleaned enough information to understand that... 1) I should not be using whole house softened water for my tanks... 2) because of my water particular conditions, I need to install an RO unit for my aquarium water

I see happy fishes in my future... & to cheat, I've made up a spread sheet with "ideal" water parameters to strive for, for particular fish, & what the different scales equal, since there are often more that one way to record the readings...

I do have one more question that I haven't really found out... it concerns Alkalinity & Carbonate hardness... heard they are treated the same, as far as aquariums go, & that's why the numbers are the same for each reading on my test strips... but is there any way of changing one reading, without changing the other... in other words, for example, is there something, ( that is safe for the fish ) that could be used to increase carbonate hardness, that wouldn't increase the Alkalinity also??? I'm assuming it's actually the Carbonate hardness that acts as the buffer for our pH, & the Alkalinity is the result of raising or lowering the carbonate hardness, & the the Alkalinity in it's self, doesn't actually buffer the pH??? did I explain the question OK???

@TwoTankAmin wrote in his post the ansswer...alkalinity and carbonate hardness are the same thing. Many water authorities use Alkalinity, and the hobby has been using carbonate hardness which is abbreviated as KH, the K from the German Karbon (carbon).

So a little more digging ( inquiring minds want to know )

Quoted off the www.

"The term “alkalinity” refers to the sum of all bases that buffer against aquarium pH swings, with carbonate being the most frequent and important base. Carbonate hardness, or KH, only measures the concentration of carbonate and bicarbonate bases."

from this statement, is it true, that there are other "basic compounds" that would / could buffer against the acids in the tank, that could swing the ph... but Carbonates are the most often naturally occurring compound... so likely the only way the 2 readings on my test strip would be different, is if I was using some other basic compound, instead of Calcium Carbonate to buffer the water??? ( not that I would... I was adding crushed coral to my aquarium gravel 15-20 years ago, even if I didn't fully understand how it was helping... )

so with straight RO water, something needs to be added, as all the buffers are removed from the water during RO Filtration, & the natural breakdown of ammonia in the aquarium creates compounds that are acidic so the water pH will drop over time... without the buffering compounds added to the RO water...

I'm wondering if I couldn't just add crushed coral ( don't know if you can even buy that today ) in my collection barrel from the RO unit, or through an inline canister before the barrel, that I'll be doing my partial water change filling from, or if adding Calcium carbonate powder, or ( I've read Sodium Bicarbonate ), would be more effective though with fighting sodium ions from my house softener previously I'm hesitant to try Sodium Bicarbonate... unless the fish need a little sodium added to the RO water

probably best off not reinventing the wheel here, & just using the Seachem product designed to convert RO water to aquarium water... ingredients towards the bottom of the label



Dang another scale... meq/ L

Magnum Man said:

from this statement, is it true, that there are other "basic compounds" that would / could buffer against the acids in the tank, that could swing the ph... but Carbonates are the most often naturally occurring compound... so likely the only way the 2 readings on my test strip would be different, is if I was using some other basic compound, instead of Calcium Carbonate to buffer the water??? ( not that I would... I was adding crushed coral to my aquarium gravel 15-20 years ago, even if I didn't fully understand how it was helping... )

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I am not a chemist, so I will let someone like @TwoTankAmin respond to this question of other buffers. In the hobby we use calcerous substances, I used dolomite, some use crushed coral though that is not the best. But others can deal with this.

Magnum Man said:

so with straight RO water, something needs to be added, as all the buffers are removed from the water during RO Filtration,

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No, not necessarily. It depends upon the fish species. All of the soft and very soft water species evolved in water with basically zero GH and KH. For 30 years my tap water was zero KH and less than 1 dGH. I kept and spawned fishes from such water, very successfully. Ian Fuller the corydoras authority spawns cories in RO water with no remineralization. @seangee does the same, uses straight RO water. The fish that cannot be kept in such water are those requiring hard water. It is no surprise, or at least it shouldn't be, that very soft water is almost always on the acidic side. There are always rare exceptions. But the two generally go together.

Magnum Man said:

the natural breakdown of ammonia in the aquarium creates compounds that are acidic so the water pH will drop over time... without the buffering compounds added to the RO water...

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The decomposition of organics from all sources creates CO2, and this produces carbonic acid, so the pH naturally drops. Left alone with no buffering (as in using RO) it will lower quite a bit. I leave it alone. The fish evolved in such water, why would they need different? They don't. Provided they are species from such water. The pH in the Rio Negro is in the 4's. This river is the largest blackwater river in the world, and there are dozens, maybe hundreds of fish species thriving in this river.

Magnum Man said:

I'm wondering if I couldn't just add crushed coral ( don't know if you can even buy that today ) in my collection barrel from the RO unit, or through an inline canister before the barrel, that I'll be doing my partial water change filling from, or if adding Calcium carbonate powder, or ( I've read Sodium Bicarbonate ), would be more effective though with fighting sodium ions from my house softener previously I'm hesitant to try Sodium Bicarbonate... unless the fish need a little sodium added to the RO water

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Crushed coral is not a good buffer. Dolomite is. You want calcium and magnesium. Not sure why, again I'm not a chemist, but I learned this years ago. Using straight RO is certainly simpler, less risk. No mixing to get the GH, KH and pH the same at every water change. I've done this a couple times for specific reasons, and it is a lot more work and bother. I've been lucky to have almost RO water come out of my tap, and the two times I did buffering and increasing GH/pH were for livebearers and rift lake cichlids. But never for soft water fish.

Sodium bicarbonate is not a good buffer. Stan Weitzman in an article on spawning soft water fish says not to use it because it is not permanent, the organics will increase regardless, and the sodium will harm soft water fish.

Add the crushed coral- it is calcium carbonate:

Most structures that we call "coral" are, in fact, made up of hundreds to thousands of tiny coral creatures called polyps. Each soft-bodied polyp—most no thicker than a nickel—secretes a hard outer skeleton of limestone (calcium carbonate) that attaches either to rock or the dead skeletons of other polyps.

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How coral works in regards to pH has to do with acidity. Acid dissolves coral. The more concentrated the acid, the faster it works. So when we add crushed coral either to the substrate ot in a bag in a filter, the more acid out water might get, the more faster the coral dissolves. Calcium carbonate is what holds up the pH in our tanks. Ro water should have 0 carbonates. So we can reduce the KH of tank water by mixing in some amount of RO. What is not good is to use 100% RO. Btw- if you do use crushed coral in a filter, it gets used up over time and it must be replenished.

I run an RO/DI unit (DI - deioninizing). This make pure water which should be 0 HK and neutral pH. The fact is unless in a vacuum. it is not at these levels. As soon as there is dissolved CO2 in water there is some amount of carbonic acid created. And this causes the pH to drop. I have to use digital testers to get good readings since I also stain the water in the tank where I mix in the RO/DI. (Color based tests do not work well, or at all, in stained water.) My RO/DI also works to lower the TDS of the water. TDS is a better measure of what is in the water than either KH or GH, However, TDS readings give no information on what is causing the reading to be at any given level. However, TDS counts everything, even ions like ammonium, nitrite and nitrate amongs other things in the water.

Unless one is keeping rift lake cichlids, we do not usually need to add sodium chloride to our water. This is re FW not SW. I occasionally have to add a very small amount of baking Soda to water, but it so small it doesn;t have enough sodium to be a concern. It is not even enough to raise the pH by more than 0.1 if at all. Sodium does not evaporate it takes water changes to remove it.

Magnum Man said:

I do have one more question that I haven't really found out... it concerns Alkalinity & Carbonate hardness... heard they are treated the same, as far as aquariums go, & that's why the numbers are the same for each reading on my test strips... but is there any way of changing one reading, without changing the other... in other words, for example, is there something, ( that is safe for the fish ) that could be used to increase carbonate hardness, that wouldn't increase the Alkalinity also??? I'm assuming it's actually the Carbonate hardness that acts as the buffer for our pH, & the Alkalinity is the result of raising or lowering the carbonate hardness, & the the Alkalinity in it's self, doesn't actually buffer the pH??? did I explain the question OK???

Click to expand...

Most species don't actually care too much about pH and can tolerate a wide range (with no ill effects). What they cannot tolerate is large swings.
As mentioned before I do water changes every week (unless I am away which is never more than 3 weeks between changes). The pH in all of my tanks is perfectly stable although I have no buffering (KH=0). Each tank has established its own eco system and although they are theoretically identical (substrate, plant density, stocking density etc), they do all have a different pH - but contant over time within each tank.

I found the same thing, in a fish room of 8 tanks, each with play sand, wood and plants, and comparable sized fish species, the pH was different among the tanks but in each tank it never varied more than one or two decimal points during the 12+ years I tested it periodically. That is stability, achieved because we let nature do it and don't interject substances to affect it.

A booster pump ( for lower water pressure ) RO filter unit on the way, along with a water pump, for pumping filtered water out of a food grade plastic barrel, for water changes... so the process begins next week... thanks everyone for all the info & comments

I'm installing a pressure booter pump RO unit in the work area for my aquariums right now... the tank & faucet that comes with the kit are extra, maybe I can use the tank for extra capacity on our drinking water RO unit... I'll be using a graduated, food grade, 30 gallon, translucent barrel, instead of the tank that came with the system... I'll be starting, just adding RO water for the 1st water change, once it's operational... of course monitoring both the RO water, & the tank water conditions... once the tanks water conditions are at goal, I'll be blending in Seachem Replenish to match my goal water for the tanks I'm doing water changes on... I used to do all of the tanks at the same time, but now I'll do the water changes of matching water condition tanks, that I've preblended a match in the barrel... I may add a barrel agitator to facilitate the blending of the Replenish evenly in the barrel prior to water changes... I have a food grade water pump to pump the water from the barrel to the tanks...

off into the great unknown...

RO unit installed, mix barrel behind it, under the stairs…

RO rinse water, to dispose

House softened tap water today

RO rinse water, run into the bucket I use for water changes
Iron… 0
Copper… 0
Nitrates… 0
Nitrites… 0
Chlorine… 0
Gh … 25
Kh … 0
Ph …7.2

Softened tap water
Iron …0
Copper… 0
Nitrates… 0
Nitrites… 0
Gh …. 75
Kh … 300 ( max )
Ph …. 8.4 ( max )

I’ll fill a 5 gallon bucket of rinse water, before I start filling my barrel… so I’ll be putting off a water change for a couple days… and may do 1/2 as much as usual to start with

Unexpected issue with the RO unit… water pipes sweating… I have insulation on the lines in the house that have main water flow… this is fed off a side line that’s not insulated… even the 1/4 inch lines are sweating… humidity… I was worried that the pump was not running when I first hooked it up, but I can hear it now, when I listen right at the filter ( it’s not loud )… I’ve started filling my barrel this morning… had to cobble a line into it, as the hose that came with the unit was too short… so I’m running that hose into a chunk of bigger hose to make it to the barrel… I will buy a longer chunk of the proper size, when I go to town today… 5 gallons of RO rinse overnight… so maybe tonight or tomorrow for my 1st tanks water change

I have great well water - about 7.0 pH and the TDS are currently in the 105 ppm range, When I started in the hobby my well had 7.4 ph abd tds at about 115 ppm. Over time things changed and I was running at 7.0 and 83 ppm TDS. hat I ghave since discovered it the parameters change based on the average rainfall, When we had a series of torrential rains over abut a two week period I saw the TDS drom in the 50 ppm range.

I started mixing my tap and my RO/DI water 50/50. About 2 years ago I found the pH was bouncing up to much between water changes. So I went to an 11/9 ratio RO/Di top tap. I recently goot off my lazy butt as a result of running this years bio-farm for cycling filters giving me some unexpected readings. I discovered that the TDS were back to about 105 ppm.

Next, KH in tanks is basically carbonates and bicarbonates. This is inorganic carbon. it is used by the bacteria that handle ammonia and nitrite. It can also be used by some plants. it is also what holds the pH steady. When I make water it should be 7.o pH and 0 for both GH and KH, but this is nit the same things as conductivit or TDS which count everything including salt and ions.

If you make pure water it should, in teory tesy as above. In actuality the pH will be under 7 because as soon as you make the water it beginf to exchange gasses with the atmosphere. That includes CO2. So the pure water will test as being acid because CO2 in water produces carbonic acid ant this works to drop the pH in the absence if any KH.

One of the clues I was getting that my well water had changed params again was in the tank where I use the RO/Di to drop the pH etc. I was noticing two things on my continuous monitor on the tank. First the TDS were drifting higher than normal an the pH which tended to rise a bit between water changes was doing so faster as well. I can fix the pH with a bit of muriatic acid but the the TDS are another story. That was when I upped the RO/DO ratio.

This is this is the monitor I use, I batch my changing water next to the tank into which it goes. This lets me move the probes from the tank into the changing water to insure it is at the parameters I want. I change the parameters of the changing water based on the tank readings right before i do the change. Mostly, I am adjusting the pH.

I use the RO/DI on a tank for altum angels in which I stain the water. This makes it almost impossible to use color based testing. So I go with digital. Conductivity/TDS is a great way to measure the total of everything in the water, but it gives one no clue to exactly what things in what amounts are contributing to the total number. However, I am pretty famuliar with my water and I can usually figure out what is missing or over supplied in a given situation. For example, when I run my bio-farm I use TDS to know if I need to add more crushed coral as the TDS drops. I also know that I have too much nitrate because the TDS rises and need to change water. TDS is basically measured using conductivity which gives reauktes in microsiemens (μS.). I prefer the ppm of TDS. How it works is a formula is applied to the measured conductivity to produce the equivalent in ppms in TDS.

Good luck with it all. Sometimes I feel like a mad scientist working away in his secret lab when I get to playing around with all this stuff.