Nitrates and water changes

[seangee]

My tap water has a very high nitrate reading (50ppm). This means I do 2 x 50% water changes per week and my daily routine has become feed the dog, feed the cat, water the fish (10%) because I know I can't afford to let it go up.

Today I discovered and ordered the Pozzani aquarium nitrate filter. Assuming it works as advertised - and the reviews seem to suggest it does - is it enough to monitor the nitrate levels and use that to determine my water changing schedule? By this I mean e.g. wait till nitrate hits 10ppm then change 50% to bring it back to 5. If so what would be a good target to aim for?

Also are there any other gotchas to be aware of or test for? Reason for asking is my kitchen water filter makes no claim to reducing nitrates but does seem to. I don't use it because it also shoots the pH up to 8 (from 7.2) -and the distributors can't / won't tell me whats in it, but I have to assume its not just a carbon block.

 

[Byron]

Household filters often contain substances that are not beneficial at best, or actually detrimental at worst, to fish. It is generally advisable to avoid them and use water straight from the source.

Water changes are intended to maintain stability. Leaving aside for the moment the issue of nitrates in the source water, the more water you change the better because this will provide a more stable permanent quality. There is much more "pollution" in an aquarium beyond what we can measure as nitrates. So allowing any measurable substance to rise before doing a water change is not as good as doing larger volume (or more frequent) water changes to keep the level lower. In nature fish are not exposed to the same water from respiration to respiration, and while we obviously cannot match that except in very minimally stocked and heavily planted tanks, our regular water changes do need to be substantial to bee effective. I hope that makes sense, and I will now use nitrates as an example.

Ignoring for the moment the source water nitrates and considering just the nitrates occurring within the aquarium: If the nitrates after a water change are at say 5 ppm, you want them to remain at 5 ppm until the next water change. If they rise to 10 ppm, it is due to one or more factors: insufficient volume of water changed, insufficient number of water changes, too many fish or too large fish, overfeeding, not keeping thee filter clean, or the substrate may need cleaning. The substrate issue however is actually part of the fish load/overfeeding aspect.

If you can get the source water down to 5 ppm from the initial 50 ppm, and then in the aquarium the nitrates rise to say 10 ppm, that is acceptable provided they do not go above 10 ppm. If you can keep them at 5 ppm, better still. There is no magic number, except that 20 ppm will over time affect most (if not all) aquarium fish. And keeping nitrates as low as possible should always be the goal. We must remember than none of the fish we maintain occur in natural habitat waters with nitrates much above zero to 1 or at most 2 ppm, and their physiology is designed to function best in such conditions; nitrates slowly weaken fish (this is a general statement, and different species or differing levels of nitrates and other factors play into it). Nitrate like ammonia and nitrite is toxic to fish, just less rapid.

The Pozzani nitrate filter does sound incredible; I read the link in another thread a few moments ago. Well worth the investment when nitrates in the tap water are so high.

 

[Wills]

Hi, I am literally about to order one of these tonight They look like a great product and pretty easy to use especially the ones connected to a hose fitting.

Let us know how you get on

Wills

 

[Toney]

My water comes out of the tap with around 40ppm of nitrates.

I do my weekly wc and have quit letting it stress me out. Have even quit testing for nitrates.

Heck it's got to get to 800 to be lethal. This is supposed to be a relaxing Hobby.

My ottos and shrimp are doing just fine.

 

[Wills]

I know what you mean but, these filters are quite cheap really, dont take any extra time and do improve your water quality. You just put the filter in the middle of a hose when you refil the tank or buckets.

I've been keeping a mix of south americans - some which would be described as quite delicate with good success for 8ish years and I have 40ppm in my tap. While I dont feel that is something to loose sleep over I do think using such a simple product is worth the little bit of effort required. And like Byron explained in my thread, long term higher levels of Nitrate does cause issues with shortening life span and growth.

If the only other option was to go full RO and it wasnt such an easy change to water changes I would maybe be closer to where you are.

Wills

 

[seangee]

Ignoring for the moment the source water nitrates and considering just the nitrates occurring within the aquarium: If the nitrates after a water change are at say 5 ppm, you want them to remain at 5 ppm until the next water change. If they rise to 10 ppm, it is due to one or more factors: insufficient volume of water changed, insufficient number of water changes, too many fish or too large fish, overfeeding, not keeping thee filter clean, or the substrate may need cleaning. The substrate issue however is actually part of the fish load/overfeeding aspect.

Thanks. I guess that's what I meant, but as you say they are all linked. I suppose I'll just have to test regularly and see how it pans out. Wouldn't go beyond a week. I'm pretty paranoid about organic waste anyway. My filters cope fine but I don't want them converting any more ammonia / nitrite than they absolutely need to.

Just need to balance that with not exhausting the filter prematurely by pushing much more through it than I need. Guess I'll know in a couple of weeks.

 

[Byron]

Thanks. I guess that's what I meant, but as you say they are all linked. I suppose I'll just have to test regularly and see how it pans out. Wouldn't go beyond a week. I'm pretty paranoid about organic waste anyway. My filters cope fine but I don't want them converting any more ammonia / nitrite than they absolutely need to.

Just need to balance that with not exhausting the filter prematurely by pushing much more through it than I need. Guess I'll know in a couple of weeks.

Nitrates occurring within the aquarium are easy enough to deal with, as I mentioned previously (stocking species and numbers, feeding, water changes, etc). My tanks run in the 0 to 5 ppm range with the API nitrate test, and have since I began testing about 10 years ago. I rarely test now, because I know the tanks are stable and there will not be any change unless something happens out of the norm. Once you achieve a stable state, it is not difficult to maintain it.

Getting the nitrates in the source water down is your challenge. That Pozzani filter is more than worth the cost if it does what it says, and the user reports indicate it does.

It is nice to see someone who actually cares about the fish; they are living creatures and forcing them to survive rather than thrive is not responsible. This is not the hobby for everyone; many maltreat their dogs too. Sad.

 

[AbbeysDad]

Nitrates occurring within the aquarium are easy enough to deal with, as I mentioned previously (stocking species and numbers, feeding, water changes, etc). My tanks run in the 0 to 5 ppm range with the API nitrate test, and have since I began testing about 10 years ago. I rarely test now, because I know the tanks are stable and there will not be any change unless something happens out of the norm. Once you achieve a stable state, it is not difficult to maintain it...

Sure, it's easy when you have nitrate free source water and you do 50-75% weekly water changes AND have lots of plants. Much harder when you have 40ppm nitrates out of the tap.

The Pozanni filter is using an anion exchange resin similar to the API Nitra-Zorb I use in a (DIY) API Tap Water Filter (followed by an inline activated carbon filter). Similarly, it can be recharged in salt water. Typically these resins can process 5000 / source water N03 ppm = gallons. In this case 5000 / 40 =125g before needed to be recharged in a brine solution.
With the exception of the 'hassle' of pre-filtering and preheating water, it should be a successful way to supply nitrate free water for water changes.

There is also an Aquaripure Denitrate Filter. A dedicated bio-filter designed to culture anaerobic bacteria to convert nitrates into nitrogen gas. Although it's been around since 2003 and has numerous testimonials, I have no first hand knowledge of it's performance.

 

[Wills]

Abbeysdad - when you say it can be recharged? Do you mean the Pozanni one can be recharged? If so thats really annoying as Ive just ordered 3 replacement filters to last me for a while... Would I just need to run salt water through the filter? The actual filter unit looks like its sealed in a capsule so not sure if I can soak it in saltwater if that was needed?

 

[AbbeysDad]

I believe these nitrate anion exchange resins can be recharged several times with salt water, but they don't last forever. I don't have the Pozzani, so you may have to get creative. However, water goes in and comes out so...you drain the unit and find a way to fill with salt water (perhaps a small funnel into the top or tube). BTW, you can use aquarium salt or non iodized table salt to make the brine solution with warm water. I don't really have a recipe, I just make a strong salt water solution. Also, once filled, let it sit for several hours, or overnight, then drain and repeat. Leave the unit filled with the recharge solution until the next use, then be sure to flush with enough fresh water to remove the salt water.

Remember when using these type filters, you need to filter water very slowly so you'll need to prep the water of any quantity in advance - you can't just use it straight away for a water change lest it take all day!

Now as to tank generated nitrates, in addition to proper feeding with high quality foods and good tank/filter maintenance, you might find success with fast growing (especially floating) plants. They will convert nutrients (aka pollution) into plant tissue that in time you will remove with trimmings.
Failing that (or in conjunction with) API Nitra-Zorb is an excellent product at removing nitrates. It too is an anion exchange resin in pouches that go in the filter. It too can be recharged with salt water and reused several times.
However, NOTE that products like nitra-zorb does not replace routine partial water changes. We think of nitrates as bad, however, aquarium water pollution is much more than just nitrates. The decomposing organics generates proteins, carbs, fats, oils, pheromones....so we want to remove these contaminants as well!

 

[seangee]

I believe these nitrate anion exchange resins can be recharged several times with salt water, but they don't last forever. I don't have the Pozzani, so you may have to get creative. However, water goes in and comes out so...you drain the unit and find a way to fill with salt water (perhaps a small funnel into the top or tube). BTW, you can use aquarium salt or non iodized table salt to make the brine solution with warm water. I don't really have a recipe, I just make a strong salt water solution. Also, once filled, let it sit for several hours, or overnight, then drain and repeat. Leave the unit filled with the recharge solution until the next use, then be sure to flush with enough fresh water to remove the salt water.

Remember when using these type filters, you need to filter water very slowly so you'll need to prep the water of any quantity in advance - you can't just use it straight away for a water change lest it take all day!

Definitely worth knowing - thanks. May be a few months off but I'll let you know how I get on with recharging them.

The plan is to keep a bunch of 25l jerrycans in the garage and top these up after very water change, so I can turn the hose on as slow as I like.

 

[AbbeysDad]

A final note - the anion exchange media use life (between recharges) is dependent on the NO3 ppm of the source water and this may change over time and with seasons. It is also likely that the performance degrades after several recharges. Therefore, be prepared to test the filtered water every xx liters after a modest amount (and after recharging) to ensure the nitrates are being filtered out. (You'd want to do this even with new cartridges).
Also, as I mentioned, watch your flow rate as too fast a flow rate will let nitrates pass right through the resin bed.

As I mentioned, I use a re-purposed API Tap Water filter (now discontinued), filled with API Nitra-Zorb, then through an inline activated carbon filter. Here is a shot of my simple setup on the kitchen counter:

I get about 250g between recharges (but this would depend on NO3 ppm - mine right now is about 20ppm from my well).

 

[Wills]

Cool thanks for sharing all this its really helpful!

I'm planning to just connect the filter to my kitchen tap, do you think the Pozanni filter will just adjust the pressure from the tap? Or will it just go through as fast as I let it? I am creating a system to run 4 pipes off the end of the filter into 4 large buckets - how long would you anticipate 160 liters would take to run through? At the moment on a bit of a relay system I probably do 4-5 buckets filled in 20 mins.

I like the idea of using jerry cans though! But buckets are a bit easier to store...

thanks again!
Wills

 

[seangee]

I think you have to set your own flow rate. I ordered the one with the hosepipe attachment. Pozzani recommend 3 litres per minute so the best part of an hour for 160 litres. Suppose you could go faster if you have less nitrates to clear but I'll be sticking with the recommendation.

 

[Wills]

Thanks Sean bit worried as my tap is not really the best or most controlable... it may just be a case of trial and error to start with, but as long as Nitrate is going in the right direction thats whats important right. Also do you think we would be ok using a mixer tap through the filter? Just to get the water to temperature?