[kimba]

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.:icon_frow
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!:icon_frow 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.

K.C

 

[Hoppy]

All test kits need to be calibrated if you intend to rely on the results for anything important. Your nitrate test kit can't be assumed to be at all accurate, or even to work at all. It is possible that you added enough nitrates to reach the toxic level for the fish, but that isn't likely, since that level is way above what we normally dose.

I suggest you study the estimative index method of fertilizing to see if you can adapt that for your use, so you won't need to do any testing.

 

[spinycheek]

It kinda sounds like you removed too much bacteria and their nutritional requirements. Those nitrifying bacteria so essential to aquaria get starved during large water changes where all the ammonia/nitrite is removed, so unless you have a high amount of fish waste to replenish it, you can crash the bacterial population. Add to that the fact that you cleaned your canister filters at the same time, physically removing much of the actual bacteria and you ended up with too little bacteria and not enough food for the ones that were left. This would've caused an ammonia and/or nitrite spike which, to me sounds like the likely culprit.

I'm always very wary of cleaning filters and I never use chlorinated tap water to do so, as that will surely kill the bacteria. You could try staggering you water change and filter cleaning schedule so it's not a such a shock to the tank.

Sorry about your fish losses, it always sucks when they die.

 

[kimba]

I know during large water change may kill off those beneficial bacteria but I got no choice as my priorty is to counter the green water problem. It'll take some time to build up those bacteria. During cleaning of the canister, I used the aquarium water to wash the filter wool both coarse & fine ones I did not clean my bag of substrate + bio rings. Anyway to speed up the good bacteria from building up?

 

[spinycheek]

Ok, at least you're cleaning the canisters right. It would still be a good idea in my opinion to do a water change and then wait 2-3 days to clean the filter if you can do that. Not sure why your water is green, but green water is at least not harmful to the fish. I would just let the bacteria build up by themselves. There are bottles of bacteria you can buy, but by the time it arrives in the mail, your tank will probably have all its bacteria again.

Did you ever test for ammonia or nitrites?

 

[kimba]

No, I did not test for Ammonia & Nitrites. Do you think the level for both ammonia / nitrite will be high?

 

[spinycheek]

Maybe not anymore, but it's definitely possible it was high soon after your water change.

 

[balutpenoy2oy]

one thing that i know regarding green water is too much light. is your tank receiving direct sunlight, if that is the case eliminate it.

 

[kimba]

There is no direct sunlight at my tank though,but I have 3 x 150W M.H above my tank. 8 hours daily split into 2 sessions.

 

[MarkMc]

There is no direct sunlight at my tank though,but I have 3 x 150W M.H above my tank. 8 hours daily split into 2 sessions.

Yeh, that's a lot of light. You haven't told us much about your tank. Size, CO2, fish load, amount of plants, ect. There could be several reasons you have green water but less light would be the first step. Get a micron filter and UV sterilizer to clean it up then fix the root cause.

 

[kimba]

Hi Mark,
Here are my tank specs :
Dimension : 72 x 18 x 24 inch
Nett Volume : 403 litres / 106 gallon
Filtration : 1 x Eheim 2026 / 1 x Eheim 2260
Pressurized CO2 : current 24ppm
Temperature : set 26'C
Lighting : 3 x 150W M.H (8 hrs daily)
Substrate : Vulcanit Fert + Lapis Sand

Flora
Phillipine Java Fern
Cryptocoryne Spirallis
Rotala Indica
Rotala Roundifolia
Rotala sp. Nanjenshan
Echinodorus "Red Diamond"
Blyxa Japonica
Limnophila Aromatica
Pogostemon Stellatus
Tonina sp. Belem
Nymphoides Aquatica
Nymphaea Lotus Zenkeri
Barclaya Longifolia
Aponogeton Ulvaceus
Eriocaulon sp.
US Fissiden Fontanus
Suessassertang
Spiky Moss
Glossostigma

Fauna
98 Cardinal Tetras
5 Otocinclus
10 Tiger Shrimps / 10 Cherry Shrimps
6 SAEs

 

[MarkMc]

What method are you using to get CO2 into your tank? What are you using to circulate the CO2 once it's in the tank? How are you measuring the CO2 content? As I said before a uv and micron filter will help clear it up temporarily while you figure out the cause.

 

[kimba]

I'm using a DIY external CO2 reactor. As I run both canister for my tank, the 2260 outlet will go direct to my chiller and chiller outlet to the DIY CO2 reactor and back to my tank. I placed both canister returns side by side on the front side of the tank and I guess with the flow output of both canister(2026/2260),it'll be enough to circulate the CO2 within my tank. I measure the CO2 level by a drop checker(which show green) and also by the calculation using PH / KH value of the water.
Since the day after the W.C, I have manage to eliminate the green water issue with success. I do believe the that the cause for the green water is that I dose too much nitrate as the NO3 test kit I have previously was expired and giving me false readings. I'm quite reluctant to go with a UV sterilizer as I have read that it'll kill off some nutrients available for the plants. Correct me if I'm wrong.
Thank you for your advce,Mark.
Cheers,

K.C

 

[Hoppy]

A UV sterilizer does nothing to inorganic fertilizers. It might conceivably affect chelated elements, like iron, but I don't think it does. It kills living organisms. It doesn't alter the chemical makeup of fertilizers.

 

[MarkMc]

Hoppy is correct. Getting back to your original post...you mentioned that you don't have any 4dKH water for your drop checker...soooo...you really can't say with much accuracy that you've 30 ppm CO2. Do a search on drop checkers and you will see why. Increase CO2 slowly while watching fish closely and things should improve. I think it's the general consensus of most expert members that too much nitrate or phosphate is not the cause of algae outbreaks. I recently dosed phosphate instead of nitrate by mistake-about a 1/2 teaspoon !-nothing happened. I'm dosing a lot more nitrate, phosphate, CSM-B and iron than I ever did. Way more than you are dosing.