Very high pressure and hazy water - anyone know why?


Gold Supporter
Silver Supporter
Mar 30, 2016
Baltimore, MD
Hello everyone,

I really appreciate having a place to go to ask questions. I am going to try to be brief, but there's a bit of a back story that may or may not be relevant and I want to share that info just in case.

We are in Maryland where we had some very heavy rain 3 weeks ago. My pool was a bit of a mess after. We had over 10" of rain in a few hours. So I was dumping water (backwash) when I realized the pool was overflowing. (I was busy chasing water that was coming into the house). The rain finally stopped and I saw that I had a ton of mulch in the pool that had washed down out of our 2.5' retaining wall bed of plants. So I netted that all out. I was exhausted at that point, just went to bed.

I nearly died in the morning when I saw my green pool. It wasn't as bad as some I've seen, but it was green. I had two bottles of bleach so dumped them in right away before going to get more. I also had maybe 3/4" of mud on the bottom and in suspension so the next 2 days were spent cleaning the pool. Lots of bleach and filter running 24 hrs a day. I had some chemistry issues because of the amount of fresh water that was added. In addition to the 10+", there were several inches in different storms for days. But I've been working on that little by little. As of today, 3 weeks after the storm, everything is on point, except my CYA still needs to come up a little. And maybe the salt. I think that's supposed to be more like 3200 or 3400. Chemistry results below.

I was vacuuming a lot because of the mud. So of course, you need to clear the filter. Well, I thought the drain for the backwash was clogged because it would bubble up around the pump when I backwashed. That's not acceptable because the water will go into the house. So I started taking the filter apart and just hosing it down. It worked. I had that pool very clean in 2 days. At some point during my cleaning, I noticed that the GFI the SWG was plugged into tripped during the storm. Shocking, I know. So that's why my pool was green. Organics in there with no chlorine being generated.

Our pressure is usually around 10 or so. We have a main drain, two skimmers, three returns in the pool and a waterfall. If it matters, the waterfall is maybe 18" high x 18" wide. Something like that. Oh and the port for the Polaris.

Yesterday (20 days after the storm), I noticed the waterfall wasn't working properly. I checked all the valves and everything is in the right position, but the waterfall was a dribble. So I turned it off. Then I noticed the pressure was nearly 30! The builder said to backwash at 24, but we literally never get there. Even when I was doing all that vacuuming, the pressure would go up, but not 30. I also noticed the water isn't crystal clear as it usually is. I wouldn't say it's cloudy, more hazy if that makes sense. Additionally, the heater won't work - there's a warning light lit and the display reads "LO"

Tested the chemistry today:

pH 7.7
FC 5.0
CC 0
TC 0
CH 350
TA 70
CYA 38
Salt 2800

Pool math suggests 12 oz acid and 70 oz stabilizer

I'm using my husband's account, he was logged in and that's just easier. I will make sure his signature has the SWG and heater we added last year when I post and correct it if not. So bear with me a few minutes :) He travels a lot and is gone. Of course, he was gone for the storm, he has some kind of sense about these things and is usually gone when things go awry at home.

Another detail that could be relevant. My husband found that the drain for the backwash is not clogged, we think that the pipe is just insufficient for the volume. That sucks, but is what it is. This is the second time in less than 2 years that we've had a 'thousand year storm' so he wanted me to be able to backwash and not worry about the water coming in the house if it happens again. So he cut the pipe that would feed down into the drain and attached a hose to it. If I need to backwash in an emergency, I can roll the 50' hose out to the yard (it's downhill) and not worry about it. He also vacuumed and then took the filter completely out and cleaned it. (Right after the storm, I was just opening the top and using the jet setting on the hose and cleaning what I could). That was Thursday. This issue started on Saturday, 2 days later.

I am going to take the filter cover off - it's like a big egg, so just take the top half off and just look to see if I see anything obvious. But apart from that, what else can I check? I would hate to call the pool repairman, but will have to if I can't resolve this with your help. Ideas?


Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
Laughlin, NV
Pool Size
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
I suspect you have an algae bloom and it is overwhelming your DE filter.

You should backwash and add back the appropriate amount of DE. You should also do a Overnight Chlorine Loss Test tonight to see if you have an algae bloom occurring.


Gold Supporter
Silver Supporter
Mar 30, 2016
Baltimore, MD
I'm not sure why I didn't see this yesterday afternoon. Regardless, I didn't. But, when I took the cover off, there was very thick globs of DE covering that little microphone looking thing in the filter. I don't know what it is for exactly, but I never saw that before. All the DE looked very gloppy and not neatly coating the filter. So I rinsed everything down and put it back together. Pressure and everything else seems fine now.

Now for the hazy water, I suspect the SWG wasn't working, along with everything else while the pressure was so high. I added bleach the other day. Just checked the Cl now and it's fine, about 4 or 5 ppm. My pump runs about 9AM - 9PM, so there's been no chlorine generated for about 7 hours. Do you still think that's algae? I'm wondering if there was just 'stuff' (dust, pollen, etc) in suspension that wasn't getting collected by the filter? There was a brief period during my clean up that I saw something similar.


Bronze Supporter
Apr 17, 2016
Baltimore, MD
0 drop in Chlorine from just before 9 last night to 5 this morning. 5.0 ppm both times.

Honestly, I feel like the water looked better yesterday afternoon. I'll see how it looks later today. Appreciate that you took time to consider my issue and try to help.

Have a great day!
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