Water problems in heated holding tanks.

Britty · 12-01-2006, 11:02 AM

Firstly i would like to congratulate everybody responsible for the excellent forum. So far most of my questions/problems have been sorted without even asking the questions. :

I am struggling to keep the nitrate levels down in my heated holding tank. I have done regular partial water changes but cannot get any change on the nitrate level. The PH is good, ammonia is good and nitrite is also good. The water is heated to 17 degrees and pumped through a black box with 3 sponges and flocore. I also have a uv which is not currently switched on (advice from local dealer) and an air pump running.

Just wondered if anybody has any suggestions, i keep loosing fish approx 1 per week, NOT GOOD. Any suggestions will be much appreciated,
cheers,Â* Lee.Â*

brettkoi · 12-01-2006, 03:31 PM

hi britty, switch your uv back on theres no reason why you shouldnt it will help with holding back bad bacteria that will multiply when your fish get ill which by the sounds of it they are.Keep water changes going and increase them to 75% if you need to.As your water is heated your filter should eventually kick in but it takes time,use lots of filter start it will speed up the filter maturing.Use salt at 1/2 0z per gallon (normal cooking salt will do)this will protect your fish from the high nitrite.I think this information will help and sort out your problem.If you can afford one a small fluid bed filter added to your existing system WILL definately sort out your problem...What is the stocking rate of your system at the moment? Also hold back on their feed as this will only add to the problem..GOOD LUCK

Britty · 12-01-2006, 06:59 PM

Cheers Brett for your advice. i would say my stock is fairly high as the koi have been growing nicely from 2-3" to now 4-5". I have a 2nd tank ready to seperate them a.s.ap. Could overstocking be the main problem even though amonnia and nitrite are rock bottom?
As for fluid beds- i know nothing, what would you recommend. Each holding tank is about 250 gallons when full so i obviously need to have one capable of coping with this. If you could recommend a good supplier that would be excellent. Is this the sort of thing that could be purchased second hand or should i go new, as i said i know nothing about these, any info would be greatfully received.

Lee.

extremekoi · 12-01-2006, 07:09 PM

Hi Lee,
Sounds like the overstocking could be your problem, can you give us some idea of how many koi you have in the tank and what size approx they are and how many times a day are you feeding and what are you feeding them ?

Do you have an air pump running in the tank ?

Best course of action for now is large water changes.

ritchiekoi · 13-01-2006, 05:06 PM

Hi Lee
Here's a link about high nitrates that i found on the quick, that may be of help as to why you get it and possible ways to alleviate .I take it it is high nitrates & not nitrites your having a problem with as i think its not often you hear about koi dying from high nitrates. As Mark And Brett say you need to do water changes,do you have much oxygen going into tank as lots of oxygen will help & in filters, Also cut down on feeding, you can get filter mrdiums that are suppose to help with the removal of nitrates such as K1 and lithaqua .Not sure if fluid bed will
actually help with nitrates although it is ideal add on for amonnia and nitrites Maybe Mark & Brett could add their opinions on this or anyone else. What sort of reading are you getting on nitrates test. Plants are always a way eating up nitrates but do you want plants in holding/ growing on tank,cheers Richard.ps heres http://www.lonestarkoi.com/Articles/nitrates.htmllink

Britty · 13-01-2006, 05:43 PM

Cheers Richard,
Yes definately nitrAte, not saying thats whats killing the fish though The dead fish when inspected have no visible problems. I am testing with an interpet pond master kit, Amonnia is 0.1mg/l, NitrIte is 0.1mg/l but NitrAte is off the colour chart (dark maroon) 100+mg/l. The instructions say 0-50mg/l is acceptable, 50-75mg/l will cause stress. For a start it was nitrIte that was high but have stopped feeding and done regular water changes (not straight from the tap). Nitrite cam down and ammonia down, but do not really want to start feeding until nitrAtes drop.
This is the only problem that i can find that may kill them!!!!

I will take a look at the link now, cheers.

Lee.

ritchiekoi · 13-01-2006, 06:26 PM

hi again Lee
I must admit i,d be suprised if i was high nitrate that was killing the koi.How long have you had your set up running for,how many small koi 4-5" do you have in tank cheers Richard.

extremekoi · 13-01-2006, 07:06 PM

How long has your system been running Lee, its quite an important factor....

Britty · 13-01-2006, 07:35 PM

Hello again,
Â* Â* Â* Â* Â* Â* Â* Â* Â* Â* The system has been running for about 4 months. 1st 3 weeks with no fish. About 1 month ago the pump went down to about half flow rate during theÂ*night (always happens) i immediately fitted another pump from the spare tank. System was down totally for a max of 5 mins. I have a 45 ltr/min air pump runing 2 x 4" air rings.

As for stock at the moment there is 20x 2-3" 10x 3-4" and 10x 4-5" added in stages. Tank has approx 200 gallons. Local dealer told me this was acceptable, but at the end of the day he thought he was going to sell me the fish,( but he didnt).

I have never kept koi in growing/holding tanks before but is proving to be a lot more tricky than a pond.I have never had any trouble using the same system as quarrentine (unheated).

extremekoi · 13-01-2006, 07:58 PM

Sounds like new pond syndrome, are your ammonia and nitrite levels zero ?