possible toxins leaching out of my stock tanks .... sealant recommendations please

i have 6- 150 gallon plastic tanks that are made of recycled plastics . they started leaching an oil that cause a almost waxy build up on the surface of the water . 
bottom line is i need to paint them with a reef safe sealant . i need some product recommendations . 
a friend of mine had just sealed a nice koi pond but the product he used was ridiculously expensive and marketed for ponds . i need a cheaper approach.... please help

Epoxy Resin is the best and probably what your friend used to paint his pond. It's not cheap but does an excellent job. The pond version you talk about presumably doesn't contain any anti fungal chemicals. I painted all my pywood tanks with it ( 2 coats ) and 12 months on no leaks or cracks.
I don't know of any other paint that is 100% safe with marine tanks. So can't offer any other suggestions.

I was going to suggest epoxy as well. Its about the only thing I can think of.

Chad Penney - MBI Council
Agis quod Adis

what type of epoxy should I use? I have heard that rustoleum makes a 9200 that's safe but I can't find it . is there another brand or model you could recommend? I need to seal about a thousand gallons worth of tubs.
has anyone here built wooden tanks and if so what did you use to seal it?
I appreciate the help everyone
Aron

oh geez for some reason I didn't notice duck was talking about sealing plywood tanks before I posted my last post .
do you know what brand you used ?

It wasn't a brand that you will find in the US (I think). Here's a link to the site in the UK http://www.antel-uk.co.uk/tds/A1%20Pond%20Paint.html
I would presume you would find something similar there though, its fairly common.

Krylon Fusion is safe to use, not sure if it will stop the leaching though. 
 
What type of containers are they?
 

they are little giant tanks . they are a recycled poly .
i have been using one with out problems for 2 years but i think it might be a batch to batch issue with the new ones . 
krylon fusion sounds alot better than resin from a financial point of view .
im thinking a few coats might just do the trick .
i havnt used fusion yet can you lay it on thick?
 

You can spray it on thick.  
 
I was thinking the epoxy may end up costing as much as the tanks themselves  

yep that was what i was running into . i figure 200 or so to epoxy .
krylon last i checked was cheap in comparison . 
so any krylon fusion is safe ?

i also wondering if it will adhere to the tanks . have you used it on smooth plastic or poly material?

Will chip and peel easy on plastic as I doesn't soak in to get a key like on wood.

Krylon fusion is designed for plastic, in my experience it has held up very well.

I painted the dividers of an acrylic tank I made, and after 4 years, it has chipped and peeled.  No apparant toxicity, but it just doesn't last.

Can you post a pic or something?
 
How are the tanks filtered, fed and drained?
 
Are you sure it not just protein build up?  (Which is normal in a non skimmed and/or a tank w/o a overflow.)

Waking this up from the dead - I've got some Tuff Stuff tubs that I bought awhile ago that I'm going to start using. muriatic acid seems to work at about 10%.  Wear gloves.  I had the same issue (hazy in water, stuff dying) and a good soak (3-4 days) seems to have solved it.
 
Cheers

Good call on the acid . I still havnt painted my tubs yet I am glad you brought it up !
Did you use a 10 % muriatic to water or was the muriatic 10% hydrochloric Acid.?
It might be kind of a bummer if I have to use a strong solution because my tubs are indoor and really difficult to get out of the basement. The fumes from that stuff are bad

Fumes can be bad, I didn't notice much more than the smell of spray paint (still left em outside for a day to dry though).  Use 10% to water, should do the trick.  The problem with painting the tubs is that if it flakes off (the paint), the crap can then leach out.
 
Good luck!

Great topic. I've been using industrial grade polypropylene tubs for rotifers & growout. Seems to work fine without being painted. Common usage for these tubs are for washing dining utensils.