Tropical Fish Forum
Tropical Fish Keeping Help and Advice => Fishtank Filtration and Cycling => Topic started by: Etienne on July 27, 2013, 10:14:39 AM
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Hi All,
My nitrate has been going down slowly by surely in the last few weeks.
pH NH3 N02- NO3-
06-Jul 6.7 0 0 25
14-Jul 6.7 0 0 20
21-Jul 6.7 0 0 15
27-Jul 6.7 0 0 7
I'm far from complaining :D but I'm trying to understand why and what could be a long term impact.
- One of my DG died on July 7th - less fish waste -> less ammonia -> less nitrate?
- I didn't see anymore algae than before that could have "consumed" the nitrate
- My plants are still growing slowly.
Could it be a combination of plants getting bigger and one less DG which lead to a slow decrease in nitrate?
I'm also wondering if my nitrate are getting to low, would affect my plants in the future?
Should I space/reduce water change? Currently doing between 15-20L changes every week (60L tank).
Should I get more fish to increase the nitrate? (Please someone say yes! ;D )
Etienne
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There are three factors that may produce a downward trend on your nitrates.
- Filtration Nitrate filtration is a bit of a fiddle. Remove any nitrate sponges you may have in your filer and replace them with normal ones. Do this gradually so you don't upset the cycle.
- Plants require a source of nitrogen to grow. They will consume ammonia in order to do this; they compete with the bacteria in your filter. If there is insufficient ammonia in the water, they will consume nitrates.
- Water Changes This depends on the level of nitrates in your tap water. If it is less than 7, water changes will decrease the nitrates in your tank. If it is greater than 7, water changes will increase the level of nitrates, if it is exactly 7, water changes will have no effect.
You must have nitrates in your water if you grow plants. If the level continues to drop you will need to add some back in using a suitable fertiliser.
You can alter your water change regimen depending upon the points made above. It is also possible to add more fish but you must pay attention to the overall stocking levels of your tank.
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Hi Steve,
Thanks for the very detailed reply.
My water comes out the tap at 0 nitrate. My current stocking level is 58% according to the online calculator
6 cardinals
6 harlequins
1 DG
4 cherry shrimps.
I'm running an additional filter which bring my filtering capacity to 160L (for my 60L tank).
I may add a couple of cardinals or harlequins.
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Something I omitted from my previous answer. Be careful if you want to alter the amount or frequency of your water changes. The water changes are about more than nitrate reduction. They remove various organic chemicals produced by you fish and plants. They also replace the chemicals used to buffer your water from pH changes. This is especially true if your water is soft. 25-30% per week in a small tank sounds about right.
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Yeah, I'm not keen on spacing out the water changes by more than a week and I find difficult to give the tank a good vacuum clean using less than 15L (25%).
I thought about adding some ottos but I fear that they will compete for food with the shrimps. My shrimps are doing a good job at keeping the plants and deco relatively algae free, the just don't touch the glass.
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Nitrate just below 5.
Action is required, options are:
1) add 1-2 harlequins
2) add 1 harlequin 1 cardinal
3) add 1 or 2 ottos - I'll buy algae wafers for them and make a point of starting to eat cucumber in my salads ;)
4) add another kind of fish but I cannot think of any small fish that would not require a shoal of at least 6 which would start to overcrowd my wee tank
I don't want to go down the fertiliser route.
Thoughts please!
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Ultimately, adding fish isn't going to solve your problem. You will have a period where your nitrates are OK, but soon the problem will reoccur. You need to treat the cause not the symptom. To do this, you have to balance the demands of your plants with the amount of nitrates available. Two options:
- Reduce the amount of plants
- Add fertiliser
Oh, Ottos need to be kept in groups of at least 6.