Bondo or plaster to repair broken DE separation tank?

[NewHomeowner]

Hi all. I have a DE separation tank that had some cracks and ultimately, has two lip pieces broken off at the top of the plastic tank where the lid connects. As such, there is now no seal on the lid as the tank o-ring doesn’t sit against anything so is useless.

I had tried in the past to repair with putty and super glue but ultimately, the whole thing blew apart from the backwash pressure. Because this is a separation tank, I don’t use it very often except at start up for backwashing the DE filter and then the occasional backwash during the pool season. I don’t have anywhere to run a hose to run on waste so the plumbing from the tank goes back into the pool after filtering through the separation tank bag.

Problem is because of the broken lips, a large quantity of water splashes everywhere and it’s a mess whenever I have to backwash. Water shoots everywhere and quite a bit of water gathers against the side of the house and risks infiltrating into the house.

A new tank is prohibitively expensive because this is an older unit. I wondered if a repair and formation of a new “lip” at the top of the tank would work and hold up to the backwash pressure without imploding?

Would bondo work? (I have no experience with this but just assume I’d mold and sand). Aside from bondo (like what is used for cars?), does anyone else have any additional advice on repair?

 

[JohnT]

I wouldn’t mess around with a tank that can be pressurized. Failure can be dangerous. You can buy a new one for about $300.

 

[NewHomeowner]

Thanks @JohnT. It's not quite pressured really... when the multiport is set to "backwash", a 1.5" pipe moves the water through the separation tank and out another 1.5" pipe on the other side of the separation tank, back into the pool. It's effectively just a passthrough, so would only be subject to the 12-15psi or whatever the operating pressure is of the pump.

I can't imagine it would be anywhere more unsafe than it currently is, where water is shooting out in all directions from a lack of a plastic lip. Could it be worse?

$300 for what is effectively a missing 2" x .25" piece of plastic seems excessive to me given its infrequent use (and the fact that worst case, I can just drain out to waste...

 

[Bama Rambler]

You are correct that you could just bypass it and dump the water, but to reinforce what JohnT said, I wouldn't try to repair it. Even at 12 to 15 psig things can get dangerous. We're not trying to be alarmist, we're just being realistic.

 

[Bama Rambler]

If you do decide to repair it on your own. You could try a fiberglass repair kit.

 

[Richard320]

Is there a way to connect a filter bag? Something like this: Backwash/DE Slime Bag™ – 30x36” Flow rates up to 120 GPM - The Slime Bag

Then at least if you get some overflow coming out, it won't be full of dirt and used DE.

 

[Soupy]

Home stores like Home Depot have glass cloth and resin, right next to where they have wood glue and stuff. I've patched cracks in my skimmers with it, worked well.

 

[JohnT]

I would feel guilty recommending anything but a new tank. Risk may be low, but flying chunks of fiberglass are scary.

 

[NewHomeowner]

Thanks for the recommendations guys. Here is a video of what the backwash cycle currently looks like ...

(this is the "guy" I hired and yes, I did notice that he didn't bother shutting off the pump when switching modes at the multiport... he owes me a new spider gasket!!)

@Richard320, the slimebag idea is an interesting one but I have 4 returns, so would have to buy one for each. At that cost, it'd be easier to just buy a new tank as @JohnT has been recommending...
I'll try the fiberglass repair kit, as this is a separate fenced off area and we're just talking about 2 small plastic pieces that broke off.

 

[Richard320]

Thanks for the recommendations guys. Here is a video of what the backwash cycle currently looks like ...

(this is the "guy" I hired and yes, I did notice that he didn't bother shutting off the pump when switching modes at the multiport... he owes me a new spider gasket!!)

@Richard320, the slimebag idea is an interesting one but I have 4 returns, so would have to buy one for each. At that cost, it'd be easier to just buy a new tank as @JohnT has been recommending...
I'll try the fiberglass repair kit, as this is a separate fenced off area and we're just talking about 2 small plastic pieces that broke off.

I meant to use that bag inside the separation tank ,

 

[NewHomeowner]

Ha Richard, that makes a lot more sense now. Will look into it!