Inherited Old Tank Syndrome????

[YuccaPatrol]

This weekend I set up two used 10 gallon aquariums to use as fry grow-out tanks. When I first got them, the gravel and decorations were coated with a thick layer of white salt-like crystals.

I rinsed the gravel with lots of water for about 5 minutes and completely cleaned the aquariums with vinegar to remove hard water deposits.

For the past 2 weeks, I had the filters placed on my current aquariums to get them cycled and ready for the new(used) ones that I recently acquired.

My plan was to have an instant cycle by using pre-cycled filters, but now it seems that everything has gone horribly wrong!

Each of these now holds about 20 1/3 inch Convict fry.

I set them up last night and just tested the water:

10gal tank #1:

Ammonia: 0.5ppm
Nitrite: 0
Nitrate:40ppm
pH: 7.2

10gal tank#2

Ammonia: 0.25ppm
Nitrite: 0
Nitrate: 80ppm
pH: 7.2

I re-tested and double checked my test kit by testing one of my other tanks, so I know that these test results are correct. I have never actually had Nitrate greater than 20ppm in any of my aquariums, so this is a shock to me!

I am guessing that the used gravel was so incredibly saturated with nitrate that my rinsing was not thorough enough.

I am also guessing that the ammonia indicates a mini-cycle going on?

Any ideas? I am not going to do a massive water change in both of these aquariums and then re-test.

 

[Roan Art]

Hey, YuccaPatrol

Yah, I'd say you've a mini cycle. Don't forget, even if you put a filter in another tank for a while, and assuming it's not overstocked, most likely only a small amount of bacteria will colonize the new one unless you increase the bioload in that tank. They've no reason to "jump ship" from the old filter otherwise.

Since the new filters probably do have a small amount of the right bacteria, the mini cycle probably won't last long. They just need to catch up.

As for the nitrates, don't panic. Those nitrates aren't *that* high. A few large water changes should look after the problem.

Do you know what the tank was used for before you got it? If the nitrates are that high, it makes me wonder what else is in the water -- just how high the TDS might be. That worries me more than the nitrate level.

How are the fry behaving?

Roan

 

[YuccaPatrol]

Thanks Roan Art.

I was told that the tanks had been used as part of a breeding operation for Oranda goldfish. They had UGF's beneath the gravel and were full of lots of dried gross crud.

Considering that the gravel and decorations were covered with that thick layer of mineral/salt-like crystals, you are probably right that TDS is probably pretty high.

Just noticed in the original post that I saw I was "NOT" going to do a massive water change. I meant that I was "NOW" going to do it.

I just did a 75% water change in both of these tanks and will report test results shortly.

So far, the convict fry are acting absolutely normal, but I don't want them exposed to high nitrates or other unknown crud for too long.

I think I will do 75% water change every day until I feel that the water is where it should be.

Edit: new water testing results

I tested only nitrates and the 75% water change removed 75% of the nitrates! Go figure! :dance:

Tank#1: Nitrate = 10ppm
Tank#2: Nitrate = 20ppm

I'll do another water change tomorrow and these tanks should be good to go.

Oh, and to clarify the filter situation:

Tank#1 has a Penguin filter with a used cartridge from another tank
Tank#2 has a Penguin bio-wheel MINI that had been running in my 75 gal Oscar tank for over 2 weeks and had previously been running non-stop for over a year.

Both should be mostly good to go, but I know any new tank setup like this is likely to go through a mini-cycle.

At least I can sleep tonight knowing that all is nearly well with these.

 

[Pufferpoison]

i wouldn't use gravel at all for a grow out tank. Especially after having goldfish in ther, that stuff has to be nasty. Since your going to be overfeeding with the growout tank, most ppl think it's easier not to have any substrate at all and just go with bare bottom.

 

[YuccaPatrol]

I'd rather go with no gravel, but the lovely woman who is letting me set up even more aquariums wants at least a layer of gravel.

However, maybe I can use this experience to sneak the gravel out of these tanks, so thanks for the inspiration and good back-up material for my argument.

 

[Roan Art]

I tested only nitrates and the 75% water change removed 75% of the nitrates! Go figure! :dance:

Tank#1: Nitrate = 10ppm
Tank#2: Nitrate = 20ppm

Looking real good! You've got it under control

Roan