new grids--DE returning to pool

[laff66]

I replaced all my grids and now several months later I'm getting DE all over the place. I may have screwed up by not replacing them all at once, as I tried to guess which ones were leaking since I couldn't find any holes and only replaced 5. When it still didn't seem to be filtering very well I went back and replaced the final 3 that I had guessed were okay before. I haven't run the pool much this winter so there's a chance its just dirt and not DE, but I can see it coming out of the returns so I'm guessing its DE. I'm not positive the grids are the same brand either so its possible they're slightly different lengths (this happened before) but they all seem to fit into the manifold fairly well. When a grid goes bad is it usually obvious or is it possible the hole is not visible?
Is there anything else I can check that may be allowing this to happen? I can't think of anywhere else that DE could be slipping past; valve maybe??

 

[jblizzle]

What filter do you have? ... while you are at it, add all our pool / equipment details to your signature (pool-school/read_before_you_post)

DE back to the pool I think has to be a problem inside the filter (hole in grid, grids not seated, my Hayward has an o-ring, etc). A valve outside the filter would not result in DE getting back to the pool.

A problem with the backwash or multi-port valve gaskets can cause dirt to bypass the filter, but I do not think it could allow DE to get out.

 

[laff66]

Guess that would have helped! I could have sworn I entered all that stuff a long time ago- sorry about that! It's a 60ft Hayward DE. I just started pulling it apart. I figured I'd at least have to look at the grids again so here goes again. They appear to be seated well, so once I get the grids cleaned up ill let you know what I find. Thanks!

 

[jblizzle]

Check the o-ring on the PVC pipe inside. I have had that become stretched out and then not fitting in its "valley" ... make sure you lube it before you put the top back on. That could be allowing DE to pass by.

 

[laff66]

I did all that last time I had it apart but will definitely check to make sure it did t get hung up or torn when reassembling it.

 

[laff66]

I thought of something else I should have mentioned. Weve had the pool 7 years and I've always run the pump daily even in winter. It is such an incredible beating to do so when the leaves drop in the fall, wind blows junk into the pool, and the trees start budding, that this year I came up with the brilliant (!) idea to just turn it off. I would just occasionally run it manually when there were things floating, then turn it off until needed again. This seemed to work fine with low water temps, as I didn't really get any algae. My question is, whether there is something about this practice that could cause the cloth on the grids to degrade suddenly? I did let the freeze protection function as it should so there shouldn't have been any damage from expansion. I wasn't really shocking it or anything that would cause the chlorine in the filter to be crazy high either. The stabilizer was low a few weeks ago so I added some and thats when the water clouded up and remains that way today.
sorry for all the extra info, but if that rings any bells for someone I'd love the input....

 

[jblizzle]

That should not cause damage to the grids. Although, not circulating the water and maintaining enough FC could allow algae to start to grow, even if not noticeable.

I would recommend preforming the Overnight Chlorine Loss Test (OCLT) ... see Pool School to confirm that the cloudiness is not due to algae in the water.

 

[laff66]

Thanks, I'll definitely do that. I'll have to get the kit though as I only have strips and the usual cheap-o test kits. according to them, the chlorine has been holding steady for at least a week. The stabilizer is really low though, even though I added some at the beginning of this mess.

 

[jblizzle]

Yes, I would have to say that ordering one of the recommended test kits would certainly be a good idea and help you KNOW what is going on in the pool.

 

[laff66]

well Crud. Dont know how I missed this the other day but theres about a 2 sq in hole blown in the top of the manifold. Dont know how that happens but problem solved.