Water chemistry impact on cichlids

[Fevz]

This thing is bothering me since the begining of my experience with cichlids. So here it goes.
I have a 106 gallon tank with 3 uarus 2 geo. steindachneri and 3 red heads. I only use tap water for them and it' relatively ok.
It's measurments are:
kh 10; ph 7-7,5; NO3 20

So my question goes like this. How do this water chemistry affect my cichlids on long term? Because most of them new lower ph levels and a bit softer water. Not to mention big NO3 levels.
I will buy denitrator for lowering nitrate levels, but i don't know what to do with ph levels?

[glaive]

If your are thriving then I would say to leave the pH, hardness and alkalinity alone.
It is better to have stable chemistry that is a little outside perfect than to attempt
to keep it perfect and have it go wrong. You could get a GH reading for us, though I am guessing by that chem the GH shouldn't be too terribly high.

The nitrates at 20ppm are acceptable. I personally prefer them lower but in the real world anyone keeping levels below 50ppm is doing a good job for their fish.

The papers I have read about nitrate levels and immune system damage are prolonged exposures of much higher concentrations. For American pan fish (various bass etc) the danger levels were 200ppm for say a month, this would vary for our cichlids. I like to consider 100ppm a more serious danger area for our fish. Add to that that anything over 80ppm typically takes more drastic measures to reduce. I have had a peek at other studies but have to stay tight lipped as the results have not been published and if I hope to stay privy to such info I will respect those who trust in me. Lets just say aiming for well below 50 is good for developing fry. So long as you maintain steady chemistry lots of water changes are a serious benefit for the young. This will reduce nitrates and hormone concentrations in the water.

[bobrfish]

Tap water containing 20 ppm nitrate is too high, first find a method to bring this down to 10 ppm or lower at all times.
In Western countries there are multiply products that could reduce free nitrate and other products that would deionize water including nitrate. Thus the water would be soft and pH would also come down.
Look at Aquarium Pharmaceuticals Nitra Zorb
http://aquariumpharm.com/Products/Product.aspx?ProductID=95
and
Aquarium Pharmaceuticals Tap Water Filter
http://aquariumpharm.com/Products/Product.aspx?ProductID=97
Both are anion/cation exchange resins. Perhaps similar resins could be found in Slovenia.

Once the nitrate is removed, another method to soften water and lower pH is use of peat, wood and other decaying plant matter that release humic acids.

[bobrfish]

Alex, there are publications showing that nitrate is toxic to amphibians starting at 7 ppm. The lowest nitrate concentration I could find for fish was 80 ppm when toxicity started. In general, science suggests a 10 fold reduction from lowest toxic effect is the upper limit for exposure.
Also to my knoweldge, no one has yet published any evidence that there are phernomes or hormones released by fish into the water column at any time. Nevertheless, we read anectodal evidence that when one group of cichlids are spawning, another group will also be induced to spawn. Perhaps the signal is milt or mucous accompanying egg deposits.
One of the early proponents of phernomes in water column inhibiting growth of fry is now suggesting that it is nitrate concentration that inhibits most but not all fry from growing. Their is no evidence at lower nitrate conc (< 80 ppm) to support this notion at this time.

[Fevz]

Thanks for the answers guys.
we have some sort of filter media that reduces nitrates, but i think it's a waste of money for such products. I am aiming to place a denitrator to my aquarium to reduce nitrates to at least 10

http://aquaria.co.za/shop/images/reeftek_denitrator.jpg
Device looks like this one. And i'll probably do it by myself.
About the ph and water hardnes. I have thought of using peat, but i have a feeling that it will ruin stability in my aquarium. Because we don't have good peats in Slovenia.
I'll try to search for some in Austria.
And i'll post carbonate hardnes test tomorrow morning (It's 2 am in the morning here:) )

[Fevz]

Did a test today of total hardnes and it's a 13 gh.