Cant get my 140ltr to settle, nitrates high, fish dying???

[Marne]

We have lost 4 fish over the past week, water was testing fine up until yesterday where nitrates were high.

Not sure whats going on, could it be the treatment for ich that has killed of the bacteria? how do i get it settled again?

We have lost 2 mollies (bith were pregant) and 2 of my older guppies. I'm worried about my plec but he's a fistey thing and i cant catch him, should i move him to my fry tank (which seems to have the best water quality out of all 4 tanks), he wont eat my fry will he?

I have started doing 50%+ water changes each day until it settles but another molly is looking poorly (my last female), i'm worried i will end up with no fish but worst would be loosing my plec.

The only fish who seems fine is the male molly which was the one who i was treating in the first place for ich (he's happily swimming around).

Have you checked your tap water nitrAte? Protozin isn't likely to have killed off the bacteria and if it had then you'd be noticing a spike in ammonia and nitrIte, not nitrAte.

What is the nitrAte level in the tank? What are the other water parameters? How many fish are in there?

Will test it again now and get back to you. theres only 5 guppies, 2 mollys and the bristle nose (he's only 2-3" long), i have a feeling one of my mollys will probably die before the end of the day .

N03-100 (in both tap water and in the tank)
NO2- 0
GH-16
kh- 10
ph-7.6
Cl2-0

So does that mean the problem is in the tap water?

Holy crap, that's high. Yes, the problem is the tap water. Do you know if it's always been so high? Water changes won't make any difference if the tap water nitrAte is that high but you can get stuff to lower the nitrAte. I've used the tetra stuff before (think it's called nitrAte minus?) when I was away on holiday. The blurb says you can go for 6 months without doing water changes, which is obviously bobbins, but it's good for lowering nitrAte if/when you need to.

You could try planting more plants in there (do you have any real ones?) to help use up the nitrAte or another option is to get a reverse osmosis unit to remove the nitrAte, but then you'd have to add trace elements so might work out the same price to keep using nitrate minus or similar. It depends on whether your tap water nitrAte is always 100 or whether it's a temporary glitch. You could email your water company and ask.

I have one real plant in there. I will get something tomorrow to put in the tank but its not looking good for the fish, if anything the tap water is slightly higher than the tank, never had a problem with the tap water before. Did a water change on my other tank today so have probaably put that at risk too. I think i will try and move the plec upstairs as i havn't changed the water in that takn for almost a week and readings are ok. Will he be ok in a 40ltr with fry until i get the tank sorted?

Hopefully its not too late to save a few fish

How big is he? If he's small enough to not eat the fry then it should be OK. Fingers crossed for your fish :( Hope you manage to save them.

He's about 3 inches (not that big), at the moment he is hiding, i'm worried as he has been extra lazy the past few days (have hardly seen him), tried to catch him last night but he darted under a rock , hopefully he will come out and i can catch him. My fry tank has 8 baby guppies which are now quite big (so wont get eaten) and 5 baby mollys (2 weeks old).

Is nitrate harmful to humans?

Will go to the fish shop tomorrow morning and treat the tank/s ASAP. The fish in my other tank are not looking great either .

dwi.defra.gov.uk/consumers/advice-leaflets/nitrate.pdf

Hmm, this link says the legal limit is 50 mg/l which is around 50ppm (I think!), if you're worried then I would phone your water company.

I'm using test strips so not tha reliable. I think i will take a water sample to the aquatic shop or pets at home (do they do testing) in the morning and if they think its over 50 i wall call the water company, i dont want to call them sounding like a mad woran if i am wrong .

Sorry, here- dwi.defra.gov.uk/consumers/advice-leaflets/nitrate.pdf

The home test kits aren't 100% accurate though.

Acording to Wessex water (our water company), nitrate in our area should be 26.9 . I wish i had a better testing kit.

Have now done several tests and consulted dh, he thinks its closer to 50 but i think its inbetween 50 and 100 (so probably not as high as 100 but deffently more than 50).

Have treated 2 of my tanks (didn't realise how much i needed to treat all 4 but luckily the 2 small tanks seem ok), the poorly molly seems to be a little bit beter, she's swimming a bit more and isn't just sitting by the filter. How long will it take to settle down? have also bought some plants which will hopefully help.