Overthinking a New Filter

[BodeFamily]

I have a 30,000 gallon pool with a Hayward S210T sand filter and a 1HP single speed pump, and lots of trees nearby. I'm planning to upgrade my filter for this summer, because the one I have seems undersized. I have 4 grimy kids and their friends using my pool, and I have to backwash several times a week if not daily during our swim season. Sometimes if they are swimming for a long time, I have to backwash a couple of times while they are still in the water. This is true even after opening up the filter to deep clean the sand and adding skimmer socks.

Before I upgrade, I want to make sure I'm thinking through everything.

1. I think in order to get bigger capacity, I will need to switch to Cartridge of DE. I have no problem with sand, but the location of the filter is near a door, and if I get anything with a bigger diameter it would block the door. So it seems like a higher capacity sand filter is out. I'm thinking of either getting the Clean and Clear 520 or the DE Quad 100 - just need to decide if I feel like dealing with DE.

2. I've noticed most people who have cartridge or DE filters have variable speed pumps. Since mine is a single-speed, is that going to affect the filter performance in any way? Clog it up faster? If I'm going to end up cleaning cartidges as often as I backwash now, there's not much reason to change in my mind.

3. We do have some iron in the pool from the fill water. I don't think the filter makes a difference for dealing with metals, but figured it was worth mentioning.

If there is anything else I should consider, let me know. I'm a chronic over-thinker, so feel free to tell me to chill out and just get a filter and it will be fine!

Thanks!

 

[YippeeSkippy]

Yes, I would say your filter may be undersized for that size pool and such heavy use. When you backwash, what is the reason you're doing it? What's actually happening at this time? We normally only backwash when the filter pressure rises 20-25% over "Clean Pressure". I'm just wondering if you're backwashing unnecessarily as a "slightly dirty" filter actually works better than a scrupulously clean one.
Another trick is to use a small bit of Pool DE as a top layer to your sand to improve filtering of the smallest stuff. It might be worth trying before you go shopping for new filters.

Add DE to a Sand Filter

A clean pool filter will increase the efficiency of your pool! ... your filter are to backwash it, clean the manifolds and grids, and add new DE.

www.troublefreepool.com

Can you give us a full set of test results so we can help piinpoint if that might be your problem? (perhaps your last before closing?)
FC
CC
pH
TA
CH
CYA
Salt if applicable

The advantage to a variable speed filter is in energy savings. You can run it 24/7 for probably a fraction of what your single pump costs.

Maddie

 

[YippeeSkippy]

Also...if you want to remove that iron...

From brown to 😍😍. Thank you polyfil!

We filled our pool from our well. We knew the risks and knew we would have a battle when the water was 12" deep as it looked green from the metals. Our fears were confirmed when we added chlorine and the water turned brown almost immediately. Enter 5 gallon polyfil filter. It worked...

www.troublefreepool.com

 

[1poolman1]

You want the largest cartridge filter you can fit into the area. Your single-speed pump will have some influence on the frequency of cleaning, but not as much as with that tiny 2.1sq. ft. sand filter. That's a filter rated for 40 gpm. Your pump is trying to move at least 50% more than that. It clogs the filter quickly.

I used to have a pump similar to yours with a 300 sq. ft. filter. There is a lot of foliage in my yard and even then I only had to clean it twice a year. Now, with a 420sq. ft. filter and VSP its once a year unless we get the kind of wind storms we had in December which meant an extra cleaning this year.

As my water company is supplied with water from wells there is a lot of iron in it. Never been an issue. Just maintain the water chemistry properly. If you are concerned, there are many sequestering and/or chelating products that can be added to pool water to mitigate issues.

 

[BodeFamily]

Yes, I would say your filter may be undersized for that size pool and such heavy use. When you backwash, what is the reason you're doing it? What's actually happening at this time? We normally only backwash when the filter pressure rises 20-25% over "Clean Pressure". I'm just wondering if you're backwashing unnecessarily as a "slightly dirty" filter actually works better than a scrupulously clean one.
Another trick is to use a small bit of Pool DE as a top layer to your sand to improve filtering of the smallest stuff. It might be worth trying before you go shopping for new filters.

Add DE to a Sand Filter

A clean pool filter will increase the efficiency of your pool! ... your filter are to backwash it, clean the manifolds and grids, and add new DE.

www.troublefreepool.com

Can you give us a full set of test results so we can help piinpoint if that might be your problem? (perhaps your last before closing?)
FC
CC
pH
TA
CH
CYA
Salt if applicable

The advantage to a variable speed filter is in energy savings. You can run it 24/7 for probably a fraction of what your single pump costs.

Maddie

My last full set of results before I brought to SLAM level before closing were:

FC: 5
CC: .5
pH: 7.3
TA: 90
CH: 40
CYA: 50

If it matters, this was from mid-October.

As far as why I backwash, it's usually one of these things (or both simultaneously); either the pressure is up above 15 (my starting pressure is typically 12), or the returns are spitting air and the pump has lots of air bubbles and is losing prime. Backwashing seems to bring the pump back into normal working conditions. (Side note: I did have the lines pressure tested for leaks, and was assured there were none).

I have gone lengthy periods both using DE and not using DE to see if it made any difference in the filter clogging so quickly, and the difference was negligible. Maybe I get an extra day or 2 before I need to backwash if I don't use DE.

I've spent more time that you can imagine pouring over threads on here about iron, lol. That's all a story for another post!

 

[BodeFamily]

You want the largest cartridge filter you can fit into the area. Your single-speed pump will have some influence on the frequency of cleaning, but not as much as with that tiny 2.1sq. ft. sand filter. That's a filter rated for 40 gpm. Your pump is trying to move at least 50% more than that. It clogs the filter quickly.

I used to have a pump similar to yours with a 300 sq. ft. filter. There is a lot of foliage in my yard and even then I only had to clean it twice a year. Now, with a 420sq. ft. filter and VSP its once a year unless we get the kind of wind storms we had in December which meant an extra cleaning this year.

As my water company is supplied with water from wells there is a lot of iron in it. Never been an issue. Just maintain the water chemistry properly. If you are concerned, there are many sequestering and/or chelating products that can be added to pool water to mitigate issues.

This is helpful to hear. I'm not sure why I have such a tiny filter, other than the previous owners were in the 80s and probably used the pool more as a lawn ornament that a repository for kids and their friends! But I appreciate hearing that your foliage and debris don't wreck the filter. That was one of my primary concerns!

My iron issues are a story for another thread - I've done AA treatment a couple of times, but can't get the sequestering agents to last for more than a week or two (even keeping chlorine and pH low). It's really just a cosmetic issue, though. I'm much more concerned about getting the right filter on the pool!