Sand filter questions : Just going to replace the sand, and see what happens

[Orion7319]

When I bought my house 5 years ago and knew nothing about pools and also recovering from a car wreck, we hired a company to do some maintenance and clean the green pool we just bought. Looking back these guys really had no idea what they were doing. My Hayward s244s sand filter has always allowed some larger sized particles past it and back into the pool, for example some but not a ton of CYA granules if fed directly into the filter from the skimmer. (I know, sock method, none of us knows anything about pool care at first) Anyway. I decided to investigate today after five years (I’m not lazy, I just run in economy mode). What I found after opening it up is that the sand looks fine and looks to me to be the right grit. I discovered though that they for some reason didn’t feed the air vent tube though the proper hole in the diffuser.
Questions. I am assuming this would let a bit of debris though the hole in the diffuser (I never have sand in the pool so I am assuming the laterals are fine). Also based on the pictures is there the correct amount of sand in it? FYI, I took the pictures after correcting the air vent tube placement. Thanks for any feedback!

 

[PoolStored]

 

[Orion7319]

View attachment 597739

Ok then, looked about 6 inches to me, but I might just measure it. I got to pick up some salt anyway today. The filter is supposed to take 300 lbs. I know that I probably have lost some during five years of backwashing. I really don’t want to replace all this sand if I don’t have to. That’s why I’m asking questions.

 

[proavia]

Do a deep clean of the sand bed before adding any sand or putting the top back on.

Deep Cleaning a Sand Filter

This post will walk you through the anatomy of a sand filter, and then provide a video at the end for how to deep clean your sand filter. The filter used in the photos and videos is a Hayward S180T top mount sand filter. The images are of a similar filter. Obviously not all filters are...

www.troublefreepool.com

 

[Orion7319]

Do a deep clean of the sand bed before adding any sand or putting the top back on.

Deep Cleaning a Sand Filter

This post will walk you through the anatomy of a sand filter, and then provide a video at the end for how to deep clean your sand filter. The filter used in the photos and videos is a Hayward S180T top mount sand filter. The images are of a similar filter. Obviously not all filters are...

www.troublefreepool.com

I’m still debating rather or not I am just going to replace it or not. It doesn’t get really fine dirt out of the pool and I honestly have no idea if they used the appropriate sand or not. I’m pretty sure the guys who used it also added hydrochloric acid or something else other then MA as the smell of it about knocked me out from 20 ft away and left streaks on the now replaced liner.

 

[proavia]

If it's not blowing sand back into the pool and seems to filter okay, it's probably fine.
Try a deep clean and then top off with additional sane if needed.

 

[Orion7319]

If it's not blowing sand back into the pool and seems to filter okay, it's probably fine.
Try a deep clean and then top off with additional sane if needed.

No sand blows back pool is clear, just some larger pieces sometimes like CYA granules seem to get past it. I have no idea how they are making their way out of the filter. Multiport valve?

 

[proavia]

Those whitish granules may be calcium flaking off the SWG.

Don't dump CYA into the skimmer. Use the sock method when adding stabilizer.

 

[Orion7319]

Those whitish granules may be calcium flaking off the SWG.

Don't dump CYA into the skimmer. Use the sock method when adding stabilizer.

lol, I know about the sock method, and use it. This was a test. Also I have like no calcium in the pool. It blows some of the CYA right back into the pool, but DE stays on the top of the bed.

 

[proavia]

Ah - so you added 1oz of stabilizer thru the skimmer to test if the filter allowed it to pass thru?
How long after you added it did it pass thru?
The sand could be channeled. A good deep clean should remedy that.

Take a sample of the existing sand and compare to fresh pool grade sand.
Post a picture of that comparison.

 

[Orion7319]

Ah - so you added 1oz of stabilizer thru the skimmer to test if the filter allowed it to pass thru?
How long after you added it did it pass thru?
The sand could be channeled. A good deep clean should remedy that.

Take a sample of the existing sand and compare to fresh pool grade sand.
Post a picture of that comparison.

It did that

Ah - so you added 1oz of stabilizer thru the skimmer to test if the filter allowed it to pass thru?
How long after you added it did it pass thru?
The sand could be channeled. A good deep clean should remedy that.

Take a sample of the existing sand and compare to fresh pool grade sand.
Post a picture of that comparison.

The CYA passes though immediately. It has always done this since the day they replaced the sand. Before I knew about this site I was told to throw the CYA in the skimmer. I think it says this in the instructions of some bags as well. I’m remembering now that they used the quickrete brand of pool sand, I couldn’t for the life of me remember that before. I know about deep cleaning the filter, just haven’t because I don’t want to completely flood my shed. Don’t want to disconnect it either and struggle to get a filter with 300lbs of sand out either. When I get a heavy rain I backwash as I don’t have a pool leveler and have to dump lots of water out anyway. Sometimes this can take 5-10 minutes with the pump on full blast. Probably not as efficient as a deep clean, but it’s also always passed some stuff though it. It’s a side mount filter as well, though I wouldn’t think that would have anything to do with it.
I was reading some older threads and apparently the quickcrete sand isn’t the greatest, so I still might replace it eventually for that reason as well.

 

[proavia]

Well - if it was the quikcrete pool filter sand, I'd just replace it with a known quality pool filter sand and be done with it.
Maybe cut your losses and start fresh.

Side mount or top mount is only the MPV location. With the side mount, the stand pipe is still at the top of the filter (as evidenced by your pics).

The CYA passing thru that easily is an issue.

 

[Orion7319]

Well - if it was the quikcrete pool filter sand, I'd just replace it with a known quality pool filter sand and be done with it.
Maybe cut your losses and start fresh.

Side mount or top mount is only the MPV location. With the side mount, the stand pipe is still at the top of the filter (as evidenced by your pics).

The CYA passing thru that easily is an issue.

Yeah it’s a weird one, for sure. The pool looks great it’s not hard to manage with all my robots. I just backwashed it today and it’s running at 15 PSI with the pump maxed out (3psi at 2000rpm). It catches DE and holds it, but whenever I use DE, my flow rates drop significantly in about a week. I have to ramp up the pump speeds by a lot or backwash at that point. I think I will replace the sand, with the stuff sold at ACE.

 

[proavia]

If you are going to replace the sand - post a few pics of the old sand and new sand as a comparison.
Would be great to see if there is a marked difference.

 

[Orion7319]

If you are going to replace the sand - post a few pics of the old sand and new sand as a comparison.
Would be great to see if there is a marked difference.

Will do! Here’s the new sand… I know you can’t tell anything. Tomorrow’s going to be one of those days….

 

[proavia]

Tomorrow’s going to be one of those days….

Been there, done that!
Almost glad my 36"/700# sand filter sprung a leak after 23 years.
It was fun cutting the top 1/3 of the filter off with a sawsall and being able to just shovel the sand out instead of using a small can and reaching thru the 6" top hole.

After the filter is empty and clean - fill it 1/2 way up with water. This will cushion the laterals from the sand as the sand goes in.

 

[Orion7319]

Been there, done that!
Almost glad my 36"/700# sand filter sprung a leak after 23 years.
It was fun cutting the top 1/3 of the filter off with a sawsall and being able to just shovel the sand out instead of using a small can and reaching thru the 6" top hole.

After the filter is empty and clean - fill it 1/2 way up with water. This will cushion the laterals from the sand as the sand goes in.

At least I have a very nice shop vac! I couldn’t imagine trying to shovel out all that sand with a small can. One of the main reasons I haven’t done this before is because I didn’t have a decent shop vac. I bought the most powerful one homedepot sells. Hopefully it proves to be a good purchase.

 

[Orion7319]

So the job is done. Took me about an hour and a half total including clean up and breaks. Only took half and hour to vacuum out the sand. Laterals are in great shape. Having my pump lower than the pool helps out sometimes. I only had to open my valves to fill the filter up halfway with water before adding sand. No sand is spitting back into the pool. The old sand looks about the same as the new sand, it was probably around 50-75lbs low though. Now for the test. 8oz of CYA into the skimmer with the pump on full…. And CYA at the bottom of the pool….. well that earns an official whatever I’m done! Could be the multivalve or the way it’s plumbed. Could be cavitation at high speeds causing it who knows. Nothing really my robots and good chemistry doesn’t make for anyway. It’s just weird. At least now I know I have appropriate sand and the appropriate amount in there and I should never have to do that again…

 

[Orion7319]

It occurs to me that CYA granules are way too big to make it past the laterals. This means that somehow that at least in fast speeds a certain volume of water is completely by passing the filter somehow. This can only be occurring in the multivalve. There is no other place that the granules can by pass the filter. I have never taken a multivalve apart and this one was replaced five years ago and had always done this. I know they use a spider gasket. My best guess tells me that mine is either messed up, or that a high volume of water will get though it. Interesting though nothing gets past it in backwash mode as I never get cloudy water or debris from the backwash mode.

 

[Orion7319]

It’s been a week and a week of heavy rains. I am noticing a difference in clarity to the water to the good. I can tell when I get in and am wearing goggles. It’s like it gets when I run DE in it. I’m still getting things getting blown past the multivalve, so it’s probably not filtering as effectively as it could, however I can’t complain about the clarity of the water. I suppose either there is a difference in the quality of the sand or that erosion is a thing. I run my pump 24/7 all year, in the winter I simply put the safety cover on and call it a day. If it is possible for sand to erode, I suppose it would do so more quickly my situation.