A few months ago I built a nice 36"wx12"hx16"d divded into three compartments. I filled it and put in some guppies. within a few hours they were all dead. I am thinking that the silicone I used could be leaching something, but I didn't want to give up yet.

I let the tank sit for a few weeks, washed it out with bleach, rinsed it a few times, and let it sit for a couple weeks. I filled it again, and added a couple feeder goldfish to each compartment. The water turned cloudy white over night. I did a 90% water change every day for the past week and the water turns cloudy white within a few minutes. I am using water from my big tank which is clean.

I have used a non-aquarium silicone to repair a leak in another tank(patch is 6"x12") with no problems.

I am ready to scrap the tank if I cant fix the problem.

Is the tank cycled? What are your water params?

The water is 100% from my other tank that has been running for almost a year.

when you say 100% what do you mean could you please be more exact
what are the readings for your

ammonia
nitrite
nitrate

is your tank cycled

when you say 100% what do you mean could you please be more exact
what are the readings for below

ammonia
nitrite
nitrate

is your tank cycled

By 100% I mean it would be the same as if I put fish in my exsisting tank. I take the water from my excisting tank for the new tank. So, in theory the new tanl should be the same as the old one.

I have done this to try and eliminate the water as being the problem. If you have two glasses of water from the same sourse and one turns color, then it should be obvious that it isn't a water problem. Ever uncycled tanks don't go cloudy that, fast if at all.

Our tap water has a TDS of around 700(which is normal for this area). It also has 5-10mg/litre of nitrates. Until recently, I have never tested water and have had fish off and on for almost 40 years.

If you only used the water from the tank, then your new tank isn't cycled, water holds very little good bacteria you need something porus like filter media for good bacteria to grow and colonize on. And I think that the non aquarium silicone might have a lot do do with it too lord only knows what kind of chemicals are in it.

i am thinking it is the silicone too, but no one has told me what in the silicone would turn the water cloudy that fast. Even with no fish in the tank, it does the same thing.

It seems to persipitate the minerals out of the water. The filters get covered with mineral deposits. The same filters didn't get covered at all in the big tank.

ok that is the silicone for shure.
the type you are using is probably 'hot' silicone used for sealing mirrors and stuff like that. normally that stuff is used for aquariums made of securit, because 'cold' aquarium sealant dosent work.
if you dont want to scrap the tank, the thing that people normally do when using hot silicone is cover it with aquarium sealant or waterproof varnish.
hope that helps

Thanx for the info. I could try to cover it, or maybe cut it back and redo it with the right stuff.

If you haven't put a cycled filter on the new tank then it will be the water. Especially if you put goldfish in there, the water can easily turn white in a day. It's a bacterial bloom.

i think its the silicone, because bacteria blooms take more than a few muinets to happen

I think what ever is in the silicone is leached out. I have been doing small water changes for the past couple days and the fish are doing good. I also have used some water clearing agent to help settle the minerals. The bottom of the tank looks like it snowed.

I will be watching it very carfully for the next few weeks before I put any of my minnow fry or carp into it. I am also looking at buying a couple new tanks. It is nice to have a DIY project, but it doesn't look like it is worth the trouble(and I am not the best glass cutter anyway...lol).

Hi Brent. Sorry to hear of all of your losses. Some silicones are designed for purposes such as sealing the bathroom and kitchen, and therefore are infused with antifungal/antibacterial agents. For the bathroom and kitchen, this is a bonus. Not so much for the aquarium unfortunately.

Good luck with getting your tank up and running Brent. Keep us posted!