Nitrate problem

[Hab]

Can anyone help, I have a started to get a problem with nitrates
Ammonia-0
Nitrite-0
Nitrate-40

I have done water changes, used nitrate pads cut down on feeding have plenty of live plants. Used RO water for changes as my tap water has nitrates.
Are there any additives I can use
Should I deep clean areas of gravel or just the top
Need to sort this before it really becomes a problem.
None of my fish look stressed or listless
2 rainbow
3 harlequin rasbora
3 golden barb
3 cherry barb
3 Dalmatian mollie
4 corry
1 algae eater
100L planted tank with gravel and bog roots

 

[claudio1]

what filter are u using?,what type of rainbow fish and algae eater?,i would say the problem could be that the tank is over stocked...


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[claudio1]

i just done a quick research and rainbow fish vary from 2" to 4" and with a minimum tank size from 10 to 50 gallons,so is a big difference between the different types of rainbow fish.


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[Bbarb27]

I think 100L is equal to 26 gallons? If so, I think you are overstocked, especially with an algea eater (assume it is a plecostomus). The only way to reduce nitrates is through frequent water changes or adding rapidly growing plants. Yes, deep clean the gravel. I would suggest one section/quadrant of the tank at a time.