Pump loses water flow every couple hours

TrishaWatts

Member
Jun 8, 2017
5
Cedar Rapids
Hi all, brand new to this group, looking for any and all help! We have a 33 ft, 52 in above ground pool with a sand filter waterway pump. 1.5hp pump takes 150 pounds of sand. It's running at 18 or so psi and pumps great for about 2 hours, then we have a huge decrease in the water flow out and in. If we backwash it for 30 seconds, it'll work great again for 2-3 hours...we are just lost!
 

JohnT

Admin
Mod Squad
TFP Expert
Apr 4, 2007
9,927
SW Indiana
Pool Size
21000
Surface
Vinyl
Chlorine
Liquid Chlorine
Welcome to TFP!

A 150lb filter seems on the small side for a 1.5HP pump. May be getting dirty quickly. What does your water look like?
 

TrishaWatts

Member
Jun 8, 2017
5
Cedar Rapids
It's cloudy, our pool place in town keeps telling us to shock it but now not so sure because it's reading chlorine but still cloudy. Year 1, we had no problems. Year 2, difficulty keeping water clean, we replaced sand didn't see much improvement. This is year 3. The water had gotten clear but had some algae spots on bottom. After vacuuming a few times, water has adopted a slight green tint but is so cloudy we can't see the bottom anymore.
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
23,932
San Dimas, CA (LA County)
Your chlorine reading is probably not high enough. I'm betting you've been chlorinating with trichlor pucks and that has caused CYA to build up so high that the chlorine you add is a slap to the algae, not a knockdown punch. With algae, you need to knock it down and kick it again and again and again until it's dead. You can't let up for a second and let it get back up. If you do, you get what you're seeing. You kill some, but what's left grows some more. You end up with an endless supply of filter-clogging dead algae with no end in sight.

We have a solution. It would take me days to explain it all, so I'll just refer you to ABCs of Pool Water Chemistry to get you started. Others will no doubt send you off to read about test kits and SLAMs and the rest. That can get heavy. Instead, check out some of these threads. Scroll through and look at the pictures. Many pools had to be worse than yours, so you can do this. Just do what they did.
 

TrishaWatts

Member
Jun 8, 2017
5
Cedar Rapids
Ok, so I'm reading some of these. We bought Chlorshield for the first time this year, it did raise our cya level but we don't have a fancy test kit. Also - can we just add standard bleach rather than liquid chlorine? At a minimum of 6 gallons a day, this is getting awfully expensive!
 

JohnT

Admin
Mod Squad
TFP Expert
Apr 4, 2007
9,927
SW Indiana
Pool Size
21000
Surface
Vinyl
Chlorine
Liquid Chlorine
Ok, so I'm reading some of these. We bought Chlorshield for the first time this year, it did raise our cya level but we don't have a fancy test kit. Also - can we just add standard bleach rather than liquid chlorine? At a minimum of 6 gallons a day, this is getting awfully expensive!

Why would you be using 6 gallons a day?
 

TrishaWatts

Member
Jun 8, 2017
5
Cedar Rapids
Trying to clear the pool. For maintenance, it's like 2 a week but we can't seem to get the chlorine high for long enough to kill off all the algae. We've gone through 25 pounds of super zappit and 24 gallons of liquid chlorine in like 9 days. Over $200 already. Really hoping tomorrow shows some significant improvement.
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
23,932
San Dimas, CA (LA County)
Ok, so I'm reading some of these. We bought Chlorshield for the first time this year, it did raise our cya level but we don't have a fancy test kit. Also - can we just add standard bleach rather than liquid chlorine? At a minimum of 6 gallons a day, this is getting awfully expensive!
Pool chlorine and laundry bleach are the same chemical, just different concentrations. Bleach is 8.25% for the good stuff. If it doesn't give strength, it's weaker than that and mostly just expensive salt water. Pool chlorine is 10 or 12.5%. You'll have to crunch the numbers to see if one is cheaper than the other.

Sorry to say, but you need a fancy test kit. To kill algae at a fast enough rate to see a difference without damaging the liner or losing huge amounts of chlorine to sunlight you need a FC level about 40% of the CYA level. If you've been chlorinating with trichlor pucks for some time, or using dichlor shock, you could easily have 200 CYA. Let's be optimistic and say you're only at 100. Shock level will be 40 FC. To raise your pool just once to 40 FC will take 13 jugs of bleach or 12 lbs of zappit. Keeping it there will take even more. Using less than enough to raise to 40 is a waste of money. Not adding enough to keep it at 40 is a waste. And what if the CYA is 200? Twice as much is needed!

Without knowing the CYA level, you can't figure out whether it's cheaper to drain or treat. And if you treat, there's only one test kit that can measure FC high enough for your purposes.

Without a test kit you're working blind. You're painting a picture while wearing a blindfold. You won't be happy with the end results and all you'll have accomplished is waste a lot of paint and ruin a canvas.
 

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