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Discussion Starter · #1 ·
I've had my small Tang set-up for more than 18 months now.

Capacity: 120 litres
Filtration: Sera Fil Bioactiv 250 +UV
Substrate: Mix of regular sand and crushed coral
Rockwork: Rustic slate (around 20kg)
Plants: Two very small ones and some Canadian pondweed (I'm not good with the names!)
Inhabitants: 5 juvenile Ocellatus Gold, 1 adult Ocellatus Gold, 5 Julidochromis, 13 Dwarf Neon Rainbowfish

I don't yet have hardness or pH test kits but I know that the water in my area is very alkaline and quite hard from the tap.

Maintenance routine: Weekly siphoning of the substrate, water change of about 30 litres which, with all the rockwork displacing the water, I think may be around 30-35% change. I had naively assumed that this was fine. :oops:

I've had test kits for ammonia and nitrite since I set the tank up and cycled it but hadn't tested for nitrates until this week. I'm feeling a bit guilty as the nitrates are far higher than I would expect (or like). So far I have done the following:
Day 1: 30% change
Day 2: 30% change
Day 3: 30% change
Day 4 (today): 60% change

I've just taken another full set of readings and get the following readings. The nitrate doesn't seem to be going down at all...in fact I think this might even be a bit higher than yesterday's, and this is after a 60% change.



Am I going mad or is this still sky high on nitrates? I've tested the water out of the tap and it's zero so something is not right here. I don't think the test kit is inaccurate. I'm not overfeeding and as most of the fish I have are quite small I don't think it's over-stocked (although it is full to capacity).

Any suggestions? :-?

I will continue with the water changes but am a little concerned it will be stressing my fish (although they seem fine). :fish:
 

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Did you measures the water directly from the tap ? if not better check that too.
The Nitrate level in your tap water could be high too.
 

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Test your tap for ammonia and nitrites. These two convert to nitrates. I would do 50% wc test both tap and tank before , then wait twenty four to 48 hours before testing the tank again . You need to get a ph tester as well it is vital in keeping aquariums.
 

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Discussion Starter · #4 ·
I've tested the tap for all three and it's zero. I don't think the problem is the tap water.

How could pH affect this? I've had the water tested for pH and it's strong alkaline. I don't test it regularly myself as it hasn't changed.
 

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Ok I'm saw your test and I have to look at the conversion from mg/liters to ppm. From the picture it looks like 25/1 on nitrates. That would be 25ppm roughly.25ppm is safe for short term. How often do you do water changes before the spike in nitrates? Did you add anything new to the tank? Plants ,substrate ,rocks ?
 

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Discussion Starter · #6 ·
"Maintenance routine: Weekly siphoning of the substrate, water change of about 30 litres which, with all the rockwork displacing the water, I think may be around 30-35% change."
 

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If you want to keep your nitrates below 25ppm there is nothing wrong with doing a 50% water change or even more as long as you match your parameters exactly.
 

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I would go for 50% if you are concerned about the nitrates being high. Like I said 25ppm or 25mg/1liter is safe if changed weekley. You could try adding a houseplant to the top of your tank and just submerging the roots to soak up the nitrates.
 

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Discussion Starter · #9 ·
Ok, that's reassuring, thanks. I was panicking a bit when I saw it wasn't zero. I don't want any poisons in the water at all ideally.

I will up my weekly changes to 50%, or I might just do a twice weekly change of 30-35% instead of just once as that would reduce the shock to the fish.
 

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You actually want to have some nitrates in the tank, especially if you have plants.

10ppm after a water change and 20ppm before a water change is my ideal.

It's only ammonia and nitrites that need to be zero.
 

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Discussion Starter · #11 ·
Ok, I'll remember that. I may do another 50% change later tonight and re-test, aiming for 10ppm.

Thanks again.
 

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Water changes of 50% are nothing to fear. Many breeders do that daily. I have to disagree with Flippercon as to the necessity of a pH test kit. It isn't "vital". Handy, perhaps. I have one but haven't used it for years, as I don't consider it of any importance for the most part.
 

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BillD said:
Water changes of 50% are nothing to fear. Many breeders do that daily. I have to disagree with Flippercon as to the necessity of a pH test kit. It isn't "vital". Handy, perhaps. I have one but haven't used it for years, as I don't consider it of any importance for the most part.
True frequent wc can take place of frequent water test. :thumb:
 

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Maybe I'm colour blind but it looks like arond 15 mg's in that pic. to me. If mg is equal to ppm, that's a deccent number. Agree on the larger water changes, I take out around 90g from my 120s once a week.
 

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I have to disagree with Flippercon as to the necessity of a pH test kit. It isn't "vital". Handy, perhaps. I have one but haven't used it for years, as I don't consider it of any importance for the most part.
I disagree, unless your tap water is already within the desired range for your fish. I like to keep my tank water at pH 8.4. My tap water is 7.4, so I have to add buffer. For water changes, I'd be working blind without my pH test kit. But again, it depends on your circumstances.

Cheers,
Tom
 

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Discussion Starter · #16 ·
The water here (London) is very alkaline so it's perfect for my Tangs (although not for my rainbowfish which I admit I shouldn't have in with them anyway). Parameters should be perfect for larger changes from now on. :thumb:
 

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TMB60
What would have happened to your fish at 7.4? I used to keep wild caught gangs at 7.6 and they always looked phenomenal, no deaths, bred me out of house n home... :wink:
 

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What would have happened to your fish at 7.4? I used to keep wild caught gangs at 7.6 and they always looked phenomenal, no deaths, bred me out of house n home... Wink
Number6 - thanks, you made me realize my type-o. Meant to say my tap water is 6.4, not 7.4.
It's well water, acidic yet hard (weird). Anyhow you are right, I'd be okay buffering it to only 7.6 or so, But I started my tanks 6 months ago at 8.2-8.4 because of my research leading up to it, namely Ad Koning's books and the fish Profiles on this site - which recommend even higher to match the lake itself, 8.5 - 9.0. I thought I was cheating a little by starting out with 8.2-8.4.
It is only since then that I'm learning (and you just helped confirm it) that the fish do thrive just fine at lower pH's. My 3 tanks are doing great, but admittedly, I'm still in the "learning something new everyday" phase. It's a great process and I'm enjoying every minute of it :wink:

Cheers,
Tom
 

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Just to reiterate and clarify what's been said here-

A pH kit can be useful, but is not essential. Yes- low pH water can be "hard", just as my high pH water is very soft. From that, you can see that hardness and buffering are better indicators of water quality than pH.

Ammonia and Nitrite should always be zero... which your test kits showed. No worries.

An established tank should have measurable nitrate. If not, your test kit is not working. Low nitrate is best, but few folks see any trouble if nitrates are below 30 ppm. (And yes- ppm is the same as mg/L) Crazier folks such as me try to keep nitrates below 20 ppm.

A 50% water change rarely drops nitrate by 50%. I believe that is because of dissolution and resuspension. More nitrate is produced from fish waste when the tank is disturbed (via a water change) and clean water is, for lack of a better term, thirsty. The big difference between the new water (0 nitrates) and the water close to fish poop (saturated with nitrates) causes a diffusion gradient. Only when there are no sources of additional nitrate will nitrate concentration drop in proportion to the amount of water changed. In other words- you're not crazy and your test was working fine. :thumb:
 

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Just the last few days I noticed my nitrates getting fairly high which I had never had an issue with in the last 3 months. Water changes didn't seem to have much effect or only slight decrease. What Triscuit said is probably playing into this. After a couple days of 30-50% water changes I decided to do a major cleanup yesterday. I removed all the rock structure and could not believe the amount of poo I found under the rocks. The ones partially buried in the sand were the worse. I siphoned all that stuff out and the levels are much lower today. About 10ppm.

Will I be ok if I clean under the rocks about once a month or so? I do water changes about once a week of about 30% and siphon any waste I can find on the sand surface then.
 
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