I just did a 90% water change yesterday night due to green water. Might have been cause by adding too much Calcium Nitrate as the test kit I have is expired! (Aug 2008). So it always show around 3 ppm level of nitrates,therefore I keep on adding calcium nitrates hoping to achieve around 10 ppm. Then the green water starts.... Is that the cause? Still not sure though.
Anyway before I took the risk to change that much of water, I tried to catch all my cardinals,P. scalares,SAEs, Ottos and transfer them to a temporary tank. Unfortunately,didn't manage to get all the tetras though. So I proceed with the water changing. 3 hours later, the W.C was completed with washing / cleaning of my 2 external canister (2026 / 2260). Commission the whole set-up (filter / chiller / CO2) and added potassium sulphate(20g) & calcium nitrates(8g) for about 400 litres of water Also not sure whether is this the right amount to dose,but I base on the instruction on both products.
Eventually, all 9 tetras in the tank died!
I'm surprised nothing happen to the SAEs and Ottos which i didn't manage to catch them. So this morning, I test the water parameter and this is what I got from test kits :
PH : 6.5
KH : 3
PO4 : Nil
NO3 : 5
I went aound 2 lfs to look for those 4 dKH solution but to no avail. And base on those CO2 calculation, CO2 level = 28.5ppm (I'm not sure though). So base on my current water parameter, is there anything that I need to adjust? How about my CO2 level? Thanks for reading and hope to get some advice soon.