Sand Filter does not work

[Teapot]

Define doesn't work, and also make model, pump, pool etc

[gadfly]

Our 2nd season with our sand filter and SWG. Last year was great, no algae. This year we could not control the algae despite several superchlorination attempts. It got hot here in the SE fast, filter just could not keep up. Also, after a year the water is older and has more stuff in it and the sand develops channels that allow stuff to pass through. We backwashed, moved the sand around, removed sand and added new sand, all to no avail. I think we had mustard algae, yellow. It would go away but come back within days. Sand is the least effective filtration, algae is much finer than what sand can filter. First we added DE to the sand filter and had clearer water within 24 hours. Then we bit the bullet and installed a DE filter. Because we have a SWG it was easier to connect the DE to a separate pump. Now the SWG and DE run side by side, pool is crystal clear, chemicals are balanced. I don't know yet how it will affect our electric bill but I'm never going back to sand filtration. Wish I had known when we bought the pool. Do yourself a favor and if it's feasible switch to DE or at least cartridge. If not add DE to your sand filter via the skimmer.

[Denniswiseman]

Agreed that DE and Cartridge filter more finely, however they clog up quicker and don't filter at all when blocked with algae
Sand is easily backwashed frequently whereas DE has to be coated after each backwash
Adding DE to a sand filter is accepted practice
Your problem was your algae not the filter, you say you superchlorinated, did you Slam (Shock Level and Maintain) or just add pool store products

[Teapot]

I find his post of total of ignorance just typical.
If he learnt the chemistry and tested there would be less issues, so many sand filters in operation.
The only point I agree on is the finer filtration, linked with correct sizing of pump to filter makes life easier and that's why I advise Dr Dryden's Activate glass filter media

[gadfly]

Agreed that DE and Cartridge filter more finely, however they clog up quicker and don't filter at all when blocked with algae
Sand is easily backwashed frequently whereas DE has to be coated after each backwash
Adding DE to a sand filter is accepted practice
Your problem was your algae not the filter, you say you superchlorinated, did you Slam (Shock Level and Maintain) or just add pool store products

SLAMmed, 3 times so far this season. Tested daily with the Taylor kit. Added chemicals according to pool math. All to no avail. I believe the problem was absolutely the filter as with DE it cleared up almost immediately. I guess we all have our perspectives, experiences, preferences. I'd rather have more labor to maintain the DE filter than watch the sand filter fail to keep the pool algae-free.

[Teapot]

I am all for finer filtration, the more you strip out of the water the easier it is to maintain. If the chlorine is maintained at the correct level to the CYA level algae doesn't grow. If things like phosphate levels are reduced the pool gets easier to maintain. Finer filtration allows lower levels of chlorine to be maintained and it lasts longer (subject to the sun's UV rays burning it up).
I have successfully run my pool on 0.2ppm of chlorine and no CYA for 5 years via a chemical dosing pump.
I have also had customers maintain their pools without going green on chlorine alone because their pumps have failed so no filtration for a week or two.

[Denniswiseman]

Agreed that DE and Cartridge filter more finely, however they clog up quicker and don't filter at all when blocked with algae
Sand is easily backwashed frequently whereas DE has to be coated after each backwash
Adding DE to a sand filter is accepted practice
Your problem was your algae not the filter, you say you superchlorinated, did you Slam (Shock Level and Maintain) or just add pool store products

SLAMmed, 3 times so far this season. Tested daily with the Taylor kit. Added chemicals according to pool math. All to no avail. I believe the problem was absolutely the filter as with DE it cleared up almost immediately. I guess we all have our perspectives, experiences, preferences. I'd rather have more labor to maintain the DE filter than watch the sand filter fail to keep the pool algae-free.

You should only need to SLAM once if you follow all the criterea. Testing daily is incorrect, you need to test often to keep your FC at the shock level. Filtering doesn't eradicate the live algae it just collects the dead algae.