Pump/suction/vacuum

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savdoc2

0
Jun 1, 2008
185
NW MO
We finally have opened the pool this year, but things are going anything but smooth.

We bought a new pump last summer - the one we had (2.0 hp) would shut off when it rained and then wouldn't work for several hours, then would work again. After we purchased it, we had less rain and we ended up being gone much of August, so we never switched out the pump. Fast forward to this summer. We decided to put the new pump (1.5 hp) on and get rid of the old one. After a few issues of holes in hoses, broken lateral in sand filter, we got things running.

We have quite a bit of dead algae and dirt on the bottom, no leaves to speak of. I attached the suction vacuum.....Now we have an issue. After running the vacuum (manual or automatic) for anywhere between 30 seconds and 3 min, the system will start to lose suction and the return flow goes to almost nothing. I disconnect the vacuum, and it remains at the low suction. I then turn off the pump for a few seconds and when I turn it back on it works fine - until I try to vacuum again. During all of this the pump basket pot does not drain out like it does when it is sucking air. To further complicate things, the vacuum was not attached this afternoon, after several hours the suction was decreased by a large amount - almost like when the vacuum is attached.

My husband thinks that the 1.5 hp pump is not strong enough to run the system and the 250 pound sand filter. I have seen you all recommend smaller pumps, so I don't know what to think. I can't even find 2.0 hp pumps online. I can't vacuum the pool the way it is. I tried a new vacuum hose and it still does it. I am going to see if I can find a new skimmer vacuum plate locally tomorrow and test that. I don't know what else it could be.

Please help!
 
There is another option. You cab line your skimmer basket with an old nylon stocking. This will help catch the fines and keep them out of your filter. The downside is, this increases your time to vacuum as you will have to stop and empty/ rinse it when the flow goes down. This is the route I take when I can't seem to get that last bit of cloudiness out. Works very well, if you can babysit it for it's inevitable clogging.
 
OK, I backwashed again and it was dark green - so it did need to be done. The pressure was the same as it was when we first started it up 16.5. After backwashing it was still the same. I was then able to vacuum for a while - much longer than the past 2 days. Then it lost suction again. I backwashed - again NO pressure difference. Water was a little dirty - but not much. Vacuumed again for a much shorter time when it lost suction - pressure still the same. Backwashed and it didn't look dirty. Had to leave and need more water, so I just left it running with no vacuum. I am still confused by it all.

I had 2 pool store owners tell me that the sand filter would not filter out the dead algae and road dust that ends up in the pool. One recommended zeobrite, the other said it could be mustard algae. I don't think it is mustard algae, but I will look into that possibility if I keep having issues with the dust. Question: will a sand filter remove settled dust and dead algae? I know it is filtering out the green stuff. I did have issues late last summer and late the summer before with what I thought dust and/or pollen - I would vacuum it and it would seem to blow back into the water and make the water cloudy. If I had to do it all again I would get a DE filter, but I knew nothing when I got the pool.
 
I am impatient......I always see posted that you don't need to backwash unless there is a 5-7 increase in pressure. I am having to backwash with less than a .5 increase otherwise I have no suction. I don't understand.
 
It sounds to me like you are asking your pump and filter to do more than it is capable of unless you backwash more frequently. You are plugging up the system with dirt and debris and it cannot function normally until youi backwash and clean it out.

I know it is filtering out the green stuff
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Not really. The "green stuff" simply grows back faster than you can filter it.

As bama said, post your test results and we can help.
 

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My test results are within normal ranges. I know I am fighting off the algae, but I still don't understand the need to backwash with less than a .5 psi change in pressure.

FC 21.0
CC .5
TA 80
CH 110
CYA 50 (I have dosed it to 50 but haven't tested it yet as it hasn't been a week)
Borate 30-50
Salt 3120

Because of the SWG, I need to raise my CYA some more, but I prefer to do that in steps than

I am using the FAS-DPD test kit. I originally had the kit sold by Pool Forum, then I bought the TFTestkit, then I have purchased refills of the reagents from SPS. I have been using these test kits for 5 years now, so I do have a handle on how to read them.

My pool is clearing up, but everything I read says you don't have to backwash until a 5-7 increase in psi. I am losing suction with a less that .5 increase in psi. The last 2 times that I backwashed, the glass didn't look green or dirty - just clear. I backwashed anyway so that I could get pressure back.

My other questions still remain:
I had 2 pool store owners tell me that the sand filter would not filter out the dead algae and road dust that ends up in the pool. One recommended zeobrite, the other said it could be mustard algae. I don't think it is mustard algae, but I will look into that possibility if I keep having issues with the dust. Question: will a sand filter remove settled dust and dead algae? I know it is filtering out the green stuff. I did have issues late last summer and late the summer before with what I thought dust and/or pollen - I would vacuum it and it would seem to blow back into the water and make the water cloudy. If I had to do it all again I would get a DE filter, but I knew nothing when I got the pool.
Click to expand...
 
Perhaps the guage is faulty. Low flow in a pool almost always results in a significant change in psi. It can actually be an increase or a decrease, but if your flow gets restricted (as yours is) a working gauge will indicate that.

Question: will a sand filter remove settled dust and dead algae?
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Yes. Unquestionably.

My other questions still remain:
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I only saw the one above....what are the other questions?
 
Thanks! I will report back later today with any changes.

My robot vac came today, So I will try to use that to pick up the remaining debris - mostly the dead algae and dust. I do live on a dirt road and prevailing winds blow the dust from the road directly at my pool, so I think much of the dust in the pool is road dust. I hope the robot can filter that dust out - the second pool store I went to yesterday said it wouldn't but I don't necessarily believe him, but I do know that last year I was having issues with the "dust" exiting the return and clouding the pool then settling back on the pool bottom.
 
I got the gauge on. It immediately read 18 psi. The water appears cloudy today and I thought I would try adding a cup of DE made into a slurry to see if we could capture the smaller particles. It did not change pressure. About an hour later, I went out and the suction was gone - the vacuum was NOT in the pool. The pressure was then 19 psi. I backwashed it and it was slightly dirty. I backwashed for about 2 min and rinsed for about 30 sec. The glass was clean after about 1 min - I kept it going because I wanted to make sure it was done. After I turned it back on to filter the pressure was 17 psi. With that I calculate 2 psi difference between clean and need to backwash - nowhere close to the 5-7change I read around here. I did nt run the vacuum today and I have been keeping FC around 20. Any other thoughts?
 
About an hour later, I went out and the suction was gone - the vacuum was NOT in the pool. The pressure was then 19 psi.
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Interesting. The gauge is a direct indicator of how much water is flowing through your system. So if your normal psi is 17 (sounds about right) and you increase to 19 psi, your flow should have decreased by only about 10% or so. When you say "suction is gone", tell me what you are describing a little more...is there no flow from the returns?
 

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