Where to start?

whiter0se

Well-known member
Aug 2, 2022
71
NYC
Pool Size
5500
Surface
Vinyl
Chlorine
Liquid Chlorine
Hi all,

I’m back again with another issue, hopefully an easy one to figure out.

For the past 3 days I’ve been vacuuming the pool everyday, because every time the pump starts in the mornings, there is dirt/debris settled on the bottom within a few minutes. I’ve observed for the past few days that the dirt starts to settle right away when the pump starts. Before the pump starts in the mornings, the bottom of the pool is clear, no dirt or debris.

Here’s some context, the pump runs for about 16 hours a day (closing this week but want crystal clear before I close).
everyday before the sun goes down I vacuum the pool and make sure it is clean. The pool water does get cloudy but I leave the filter on for about another 8 hours and let it work until it shuts off for 8 hours and starts again the morning hours. Everytime I vacuum I make sure the bottom of the pool is clear and i've managed to vacuum up everything.

In the mornings, right before I start working, I go outside and take a look at the water, the bottom is just the way I left it the day before, the bottom of the pool is clear and there is no visible dirt/debris on the bottom. But as soon as the pump turns on, the dirt/debris comes back again! And it settles down in the same exact spot.

Here are my two theories;
1. The pump is way more powerful, it is a 1HP pump that moves about 75 gallons per minute. I have a cartridge filter (Hayward) that is about 18in tall (don’t know specifics). The theory is the pump is so powerful that it shoots the dirt/debris so much that it somehow bypasses the filter or maybe the dirt is settled somewhere else in the pipes?

2. The dust/debris settles in the filter enclosure near the bottom or top during those 8 hours when the pump is off. When the pump starts again in the morning it manages to bypass the filter and go back into the return.

I am going to purchase a new filter cartridge for next season but I wanted to know if at least my theories make sense and if anyone has any other tips or tricks I should try? At this point I’ve even thought about getting a shop vac and sucking up all the dirt that way but I’d have to empty it every minute or so which would probably be a lot harder.
I do not have a variable pump and unfortunately because it is a cartridge filter, there is no backwash or waste setting otherwise I don't think I'd have this issue.

Thank you
 
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I think you should get a larger filter although the way they did your equipment pad they did not leave you any room for expansion.
 
So I took the opportunity to clean the filter and the enclosure after vacuuming yesterday. Lots of greenish dirt came off the filter while rinsing it off. I added some Clorox and water into a spray bottle and sprayed, let it sit and then rinsed it off again until it was clear.

I did not take a photo but the filter seemed saturated with this greenish dust like material. Could it be mustard algae instead? I’ve kept the FC at or above 10 for the past month with LC. No one has been swimming for an entire month neither. However, we did have some nasty winds and rain (remnants of hurricane Ian) the last week so it may also be that.

I reinstalled the filter, let it run for 4 hours before I shut it off. This morning I have the same issue again - there is dirt back into the pool and accumulating in the same area. It’s not in the shaded areas of the pool so I feel like it isn’t mustard algae and this morning before the pump started, the pool was the same as I left it yesterday.
 
Have you done a Overnight Chlorine Loss Test?

Post a complete set of test results from your own test kit in the format:

FC
CC
pH
TA
CH
CYA
Ah I’ve stored my test kit away for the winter. I put a bunch of silica gels and hid it in the basement but I can bring it out. I am having the pool closed Tuesday. I’m not sure if I’ll have enough time do an overnight test. I’m just worried about closing the pool like this and opening back up to a swamp next season.
 
It might be worth it to push your closing back a week or so so you can get the pool sorted out.
I should be able to get some results tomorrow and will test against Tuesday morning. I’m hoping I do not have anything growing in there as the water does feel extremely cold and I believe mustard algae doesn’t like the cold?
 
Once it gets started all bets are off :(
I know the CYA is about 80-90 from two weeks ago and the calcium should be within reasonable range. If I just measure FC and CC for those two days, is that good enough? I have a hard time reading the pH indicator on the test kit but it’s always near the high 7s.
Edit: I posted my results sometime within the last two weeks.
 

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With CYA of 80-90 a FC level of 10 is not going to fix an algae problem.

You need to follow the SLAM Process and your SLAM FC level will be 35.
 
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