Weak Return Valve Pressure

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pabadear

0
Jul 2, 2018
21
Wayne NJ
Hello everyone! I'm new to the pool world after purchasing a house last year with an above ground pool. This is the first season I try to maintain it and so far it has been bitter-sweet.


I have a 8300 gal above ground pool with a Hayward cartilage filter attached to a 1HP Hayward power-flo LX pump. After 6 weeks of opening the pool,I have been struggling to keep the return valve pressure strong. In the past 3 weeks, I've had to remove the filter/pump from the pool, drain it, and service it to the best I can ONCE PER WEEK which has become frustrating. I check the O-rings, the baskets, the impeller, and hose down the filter. Once I do that, I reconnect everything, prime the pump, start it and the pressure is amazing again. Give it 3 days or so, and I see a drastic decrease of pressure from the return valve. My filter pressure gauge has always read around 18-19psi so I changed it last week and noticed at start-up it was around 15psi and 1-2 days later, it's floating around 18-19psi again. By the 3rd day, barely any pressure from the return valve and no suction from the skimmer but filter pressure gauge still steady at 18-19psi. I can't find a leak and considering it's a fairly simple set-up and every time I open the relief valve, there’s no air being relieved, I'm kind of ruling this out as the issue unless I'm missing something. The exterior of the filter and pump is extremely dry during operating hours.

This is the first season with a pool and the equipment was left by the previous owner after I bought the house last year. Is it possible the cartilage filter needs replacement? The mesh material seems to be in fairly good shape but there is slight wear on the blue plastic end plates. No cracks though. Pictures are attached for reference.

Any help is much appreciated! This has been driving me nuts.
 

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Welcome to the forum!

Are the pictures of the filters clean or dirty?

How do you test your pool water chemistry? Can you post a complete set of test results?
 
Thank you! The images of the cartilage is after I hosed it down, right before inserting it back into the filter, which ran great for 3 days up until yesterday.

Pool chemistry is typically checked at my local Leslie's Pool Supplies branch. I've went three times, below are the results. Aside from a tad low alkalinity and slightly over in Phosphates, do you see anything that may be alarming?

Date: 06/13
pH: 7.6
Alkalinity: 80
Cyanuric Acid: 25
Free Chlorine: 0
Total Chlorine: 0
Phosphates: 1000
Calcium: 220
Iron: 0
Copper: 0

Date: 06/28
pH: 7.7
Alkalinity: 70
Cyanuric Acid: 0
Free Chlorine: 0
Total Chlorine: 0
Phosphates: 200
Calcium: 200
Iron: 0
Copper: 0

Date: 06/30
pH: 7.4
Alkalinity: 60
Cyanuric Acid: 30
Free Chlorine: 1
Total Chlorine: 1
Phosphates: 200
Calcium: 200
Iron: 0
Copper: 0
 
The forum does not rely on Pool store tests to provide guidance.

Order a TF100 test kit
The only other real option for a test kit is a Taylor K-2006-C. Be careful comparing prices because the K-2006 comes in sizes, designated by a letter. The basic K-2006 has .75oz bottles. You need to get the K-2006-C to get the larger bottles that you want. Even then it is a little short on the reagent & powder for the FAS/DPD test.

I also have the SpeedStir. It makes testing much easier.
 
They cannot be held liable. There is no contract between you and them.

We find that many times pool store employees primary goal is to sell stuff, not necessarily get your pool in perfect condition. As to whether that is because of improper training, lack of knowledge or just to sell stuff I will leave up to you. While you would think that a "professional” would be the best, unfortunately in most cases it is quite the opposite.
 
pabadear said:
Out of curiosity, why are store results looked down upon? I would presume stores use reliable testing kits since they can be held liable, no?
Click to expand...

Just look at your results for that answer. Your CYA went from 25 to 0 to 30. The only way they could possibly be correct is if you drained your pool entirely after test 1 and refilled it but added zero stabilizer until after test 2 then added enough to get you to 30. More likely is test 2 was dramatically off. If you had based your chemical additions on that test you would have increased your CYA level significantly and the only way to reduce it would be to drain a significant amount of water.

Make sense?
 
Got it. So in the mean time, what typically decreases the return valve pressure that may be related to the pool water's chemistry? And can I get your take on the current condition of the cartilage? I've only been able to conclude that it is in good shape based on what I found on google as examples of extremely bad cartilages but they were extremely obvious so not entirely sure if mine is showing early signs or what.
 
Plugging of the filter causes your filter pressure to rise and your return flow to decrease. When the filter is plugging quickly, it is normally from an algae bloom. At its earliest stages, an algae bloom can be invisible to your naked eye, the water will just look dull or slightly cloudy.

The cartridge you show, looks fine. You can do Re: How to clean a cartridge filter to clean it more thoroughly.
 
ship of fools said:
Just look at your results for that answer. Your CYA went from 25 to 0 to 30. The only way they could possibly be correct is if you drained your pool entirely after test 1 and refilled it but added zero stabilizer until after test 2 then added enough to get you to 30. More likely is test 2 was dramatically off. If you had based your chemical additions on that test you would have increased your CYA level significantly and the only way to reduce it would be to drain a significant amount of water.

Make sense?
Click to expand...

Makes perfect sense - but again I'm new to all this so please excuse my ignorance. After the results from test 2, I actually didn't treat anything because the pump wasn't properly circulating the water anyways. I did however re-service the pump to get it to run again for a day or two to shock it because I was starting the get alge growth at the bottom of the water. When I retested 2 days later, I was shocked to see CYA was somehow at 30. I figured something may have allowed it to increase but based on this discussion now, that can only happen if stabilizer is added, correct? No other way?
 

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Depending on the 'shock' product, it could have added a bit of CYA. Dichlor and Trichlor have CYA, Cal Hypo has calcium. Sodium Hypochlorite (bleach) has water and a touch of salt.
 
mknauss said:
Plugging of the filter causes your filter pressure to rise and your return flow to decrease. When the filter is plugging quickly, it is normally from an algae bloom. At its earliest stages, an algae bloom can be invisible to your naked eye, the water will just look dull or slightly cloudy.

The cartridge you show, looks fine. You can do Re: How to clean a cartridge filter to clean it more thoroughly.
Click to expand...

Ahh - interesting. I did have an algae issue but I thought it was minor. First it was random dark spots around the pool floor which eventually increased after 1-2 days then the water clarity went away and was noticeably turning a light shade of green. I hosed down the filter, brushed the algae off, then shocked it and ran the pump which cleared everything but here I am again with a potentially clogged filter as of yesterday. Perhaps I'm not defeating the algae properly? The pool looked 10x better than last Monday.
 
When you get your test kit, post up your test results.

In the mean time, read Trouble Free Pool School. You will most likely need to SLAM Process.

Keep adding at least 5 ppm FC of liquid chlorine per day to the pool while waiting on the test kit. Do not use any more solid chlorine products.
 
mknauss said:
When you get your test kit, post up your test results.

In the mean time, read Trouble Free Pool School. You will most likely need to SLAM Process.

Keep adding at least 5 ppm FC of liquid chlorine per day to the pool while waiting on the test kit. Do not use any more solid chlorine products.
Click to expand...

Will do.

For the chlorine, why liquid and not solid? I've had 2 floating 3" tablets for the past few days. Inherited 2 huge buckets from a neighbor who took their pool down - one filled with tablets and one filled with granules - was hoping to go through them before investing in more chlorine products. If liquid is the way to go though, I'll go that route.
 
Solid chlorine adds either CYA or Calcium. Both can only be removed by draining your pool.

You can use the 'pucks' when you are going to be away from the pool for a few days. When you return you test your CYA, adjust your target level FC, and use liquid chlorine.
 
Question regarding active ingredients in chlorine/shock containing CYA while I wait for my kit. If anyone can confirm, that would be much appreciated.

I read some articles on line, specifically the one posted on https://www.co.shasta.ca.us/docs/li...t-docs/ehd-docs/Pool_Chemistry_Fact_Sheet.pdf

According to it, for solid chlorine/shock containing CYA, they will have one of the following active ingredients:
1. Potassium dichloro‐s‐triazinetrione (potassium dichloroisocyanurate).
2. Sodium dichloro‐s‐triazinetrione (sodium dichloroisocyanurate).
3. Trichloro‐s‐triazinetrione (trichloroisocyanurate).

Is this true? These are the only three indicators for CYA in solid chlorine/shock products?

I checked the solid shock I used before from Leslies and the active ingredient is Calcium Hyprochlorite and the liquid shock they had at the store was Austin's Pool Tech which contained the active ingredient Sodium Hyprochlorite. Based on the article, are both these two options CYA-free and good to use? My CYA is around 50ppm after getting my water tested at two different local pool shops (50ppm and 52ppm to be exact). I wanted to get an idea of where it was till I get my kit and start monitoring things myself.

EDIT: Nevermind - a previous post by mknauss above answers this for me.
 
Alright I got my TF Kit and my SpeedStir and for starters, it was pretty darn cool doing this on my own. Here are the results:

FC: 0*
CC: 0*
Calcium Hardness: 8 drops x 25 = 200 ppm
Ph: 7.2 ppm
TA: 6 drops x 10 = 60 ppm**
CYA: 40-45 ppm***

*I honestly did not check for any chlorine. I haven't put anything in the pool for the past 1.5 weeks nor have I shocked it and the water is now clouding up and a light tint of green. I was waiting for the kit before proceeding. I figured once I get the kit I can properly shock it and be good to go.
**This was a little tricky in distinguishing between pink and red - wasn't sure the degree of red to expect. At 5 drops it turned pink/redish so I gave it one more drop and it kind of darkened a bit more towards red so I stopped there).
***At 45 the black dot was extremely faded but still visible and by 40 it was really hard to see but I can still make it out because I knew there was a black dot there. So would I treat it as 40 or 50 ppm?


So with all that said (sorry for babbling on and on), I used the pool math calculator and this is what I should do - I think.

Based on a CYA reading of 40, my target FC is 6 - 8 ppm and my shock should be 20 ppm. I should add 59oz of 12.5% sodium hydochlorite (Austin's Pool Tech) to properly SLAM the water.
For TA, add 78oz of baking soda to raise it to 100 ppm. Is this correct? Should I do anything else? Again, this is using the pool math calculator on a 8300 gal pool.

Also question - considering my Calcium Hardness is at 200 ppm, would shocking the pool using 12oz of calcium hydochlorite 65% (per pool math) run the risk of going over the 400 ppm allowable max limit for calcium hardness?

Thanks in advance!
 
I think you want to have TA at 60 to 80, not 100 (and don't worry too much this affects pH and isn't as critical as getting rid of your algae bloom). Keep that shock level up until you pass the three criteria - CC is 0.5 or lower; you pass an OCLT (overnight FC loss test shows a loss of 1.0 ppm or less); the water is clear.

Pool School - SLAM - Shock Level And Maintain

This is the important difference between pool store and TFP "shock" procedure - TFP keeps the pool at shock level until it is actually done, pool store has you buying all kinds of junk and working all summer to clear things up (and it never really gets done, convenient for them eh?)
 
Ok sounds good! So I just shocked it using 59oz of sodium hypochlorite to get my FC tagret to 7ppm. Is that good or should I be targeting higher? I'm going to let the water circulate for 2-3 hrs then do a FC and CC reading before I go to bed. Then I'll check it in the morning to see the loss.
 
You need to SLAM Process. You stated your CYA is 50 (round up the 45) and thus your SLAM level FC is 20 ppm. Raise it to that and test every couple hours and raise the FC back to 20 ppm. If you have visible algae this will take several days to a week.
 

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