Another cloudy water thread...can't seem to fix it

[jeremyp]

I just tested again and the FC is at 22ppm and the CC is at 0.5ppm. I'm not losing >1ppm FC, but my CC isn't 0 either. I brushed the sides and floor again for good measure. I'm assuming I should keep the current course of action...keep FC > 20ppm until CC - 0? Keep brushing sides and floor? What about adding DE to the sand filter...would that help at all?

[BigDave]

Sounds like you're there, 0.5 ppm is within the error of the 10ml sample test. Sounds like adding DE is the next logical step; be sure to check if it's blowing out the returns when you add it. BTW I haven't used the cellulose product you mentioned but I did try another last year and found that it didn't help and when I opened the filter I found it in large gray clumps on the sand.

[jeremyp]

Update:
I added some DE to the sand filter last night. (About 4 or 5 solo cups)
I back washed a few times prior so I had to add some fresh water. FC is now 16ppm, CC is now ZERO and pH is 7.4. The filter pressure climbed 11 psi and flow was pretty slow so I back washed again this afternoon. Results are still the same. This cloudy water isn't getting any better at all. It still looks exactly the same. How long should it take to see results from adding DE? Did I add enough DE, too much? This is starting to get a little frustrating to say the least.

[TheGoose]

Just for comparison sake, do you know how much sand your filter holds? Mine is rated for 325# and my starting pressure is ~20 psi.

You're only supposed to add enough DE for a ~1 psi pressure increase. I overshot mine also, but I found that if you shut the pump down for a few minutes and re-start the pressure somehow will come down. Mine went up to 26 on roughly one solo-size cup, but after I let it set for ~5 minutes it was back down to ~21 psi.

[jeremyp]

My Hayward sand filter holds 300 lbs +/- and clean filter pressure is 18-19 psi. After putting in the DE the pressure did rise 1-2 psi but after a half hour or so it had climbed another 5 psi or so.

[Watermom]

Too much DE. As you found out, it does take a little time before you see the total rise -- often as much as 20 or 30 minutes. So, cut way back next time.

[TheGoose]

Shut the pump down for ~5 minutes and see if it drops after you start it up. I think the loss of flow lets the DE get more evenly distributed over the top of the sand bed.

[jeremyp]

TheGoose - I noticed that...I had shut it off for a few minutes and when I turned it back on the pressure went down but after 15 minutes or so it was back up again. I've since backwashed and this time only added 2-3 cups of DE. Next time I'll add slowly and wait until pressure stabilizes before adding more to get the right amount (thanks Watermom).

I read another ongoing thread in this forum and I feel like I'm suffering from the same issues as others this season due to, what I think may be, an oversized pump. I'm running a 1.5 HP Hayward Superpump through a Hayward S244S sand filter and, after checking with my pool installer, found out that my pump is at the upper limits of the filter specs. Last year the water was crystal clear all season long. Now that I had a seriously green pool to start and really need to filter the dead bacteria out of the water it may be pushing too hard to filter as effectively as I need it to. Although, the DE project seems to have helped some. I can now see the bottom of my shallow end...We're at least seeing some progress. I'll keep at the DE 'thing' until it clears up. I'll probably be due for another backwash by the end of the day as the pressure continues to rise (obviously a good sign!).

Thanks,
JP

[TheGoose]

My old pump was a 1.5 HP with an old Sta-Rite Swimquip DE Filter. When I switched I decided to go back with a 1-HP and a sand filter. I figured that since the filter was rated for ~60 gpm I was in good shape but now I'm finding out that I'm really at the upper level of flow for that filter and I have never really had consistent results. I'm strongly considering either going back to DE or up one size on my sand filter.

[PoolDoc]

Hi Jeremy;

+ Do NOT use celluose; it will gum your filter up something awful.
+ For good filtration of fine particles, you need to slow flow down to 45 GPM or less. With an 19 psi filter pressure, you're probably running closer to 65 GPM.
+ Short term solutions: put a valve in between the pump and filter, and throttle the flow till CLEAN filter pressure drops to about 10 psi.
+ Long term, more energy efficient solution: replace the impeller on your pump, with the impeller for an SP2607x10.
+ Long term, MOST energy efficient solution: replace the impeller AND replace the motor with an energy efficient 2-speed model -- and run on low speed except when vacuuming or backwashing.

Sand filters are never the best at small algae particles, but over-driven sand filters are the worst.

Possible quicker cleaner-upper:
1. Make sure your algae is dead (brush the whole pool) and that your FC is > 10 ppm.
2. Turn your pump off overnight. If the algae is settling, add bleach to maintain chlorine, and let it continue settling.
3. If it does not settle, return to filtering.
4. If it does settle, you can vacuum to waste.