Water loss/ algae coming into return lines while vacumming

[4Season-house]

I'll try to be short and concise. Only a year in to pool ownership and inherited a 40 yr old concrete pool. It checked out in inspection/ no diver. Had issues cleaning algae from it at the end of last season when we took over the house. Had a company close it and Put new maco cover on it (rugged mesh) and lost 40" of water through the winter. Thought there were major leaks had a diver come out. Waste of money. He said there were hairline cracks at 90 degree where floor met wall. Light and skimmers were not leaking. Tile loss were only @5 tiles at the point. I was at that point ( prior to opening) loosing @ 3/4" a day if not 1". Opened pool. Everything ran fine for a while. Equated the water loss over the winter to the pool having not been closed correctly. Smooth sailing for several weeks. I previously had a hayward 425sqft media cartridge filter with 1.5 hsp pump. Pump began to leek at juncture between the wet and dry mechanics, and we were having greater issues of water loss and algae. To be clear the pool is not with out its issues. ( some Tiles more than at opening, are down and there is visible cracking behind he tile line. Some paint is peeling as well * note previous owner said he emptied and painted pool every year* ) through all of this I was able to maintain a certain water level that kept the skimmers from taking in air into the system. Pool turned green first acid green and then full blown swamp and I was clearing the cartridges at least twice a week. I had two companies come out/get quotes and both said my pump/ filter was too small for the size pool (22x40 rectangle/ 34000 gal) bit the bullet and purchased new pump zodiac plusHP and filter de system Jandey DEV 60sqft. All went well for two weeks and then ****..

In the process of clearing the green pool, backwashing etc. When I turned on the pump I got a burst of algae back in the pool. Figured it was not an efficient backwash.. And then started to rinse. Still got algae water back in the pool. Through this adding water @every 3days on top of any rain we had.. Thus making it virtually impossible to balance chems.. I just vacuumed trying to rid the green in one of many attempts to control chems.. The entire time algae coming in through return lines as I vacuumed. I woke up this am and water Level had dropped too low for pump to prime. Had to go to work and just shut it all off in frustration. Lost and inch+ of water between 8am-6pm. Two things to note is that I have two skimmers and two returns. The skimmer I normally attach the vacuum (manual) to runs at a faster rate than the other. I am not vacuuming to waste because I wind up loose too much water to keep pump running. I don't know if I'm missing anything.. But I'm at a loss. I know I prob need to do a pressure test. Praying my returns are not cracked but I feel like I'm being taken advantage of here.. Any insights? Thanks!

 

[zea3]

Hi, welcome to TFP! I'm sorry you are having so many problems with your pool. It sounds like there are several issues going on, so I have a few questions. Some of them may seem odd, but please bear with me.
When you backwashed the DE filter how much DE did you add after the backwash was completed?
Are you turning the pump off before moving the selector lever on the multi port valve? (valve on the filter)
What do you use to chlorinate your pool?
Have you tried the bucket test to see how much water is lost to evaporation vs a possible leak?
Please post a current set of complete test results. The numbers from the results will enable us to trouble shoot problems with chemistry much more efficiently.

Please read through ABCs of pool water chemistry when you get a chance. It will give you basic information about pool chemistry.

Much of our advice relies upon water test results. We recommend a high quality test kit such as a Taylor k2006 or a TF 100 . These kits will allow you to test very high levels of chlorine which is needed during the SLAM process . The slam process is conducted to clear the pool of algae.

Please post pictures of the problem areas of your pool, pool water, and of your equipment pad. It helps us in the troubleshooting process if we can see a little of what is going on in your pool.

 

[4Season-house]

Thanks for your reply!!! When I backwash. I absolutely turn off the equipment between each stage/cycle setting. When the new filter system was installed I used DE for about 3days (6lb de each time I had to backwash when clearing out swamp like pool.) It was crystal clear. I then switched to Pure Fiber organic medium at the advise that it was fine to switch as long as a did a really thorough backwash. The first two times is did this, I wasn't adding enough medium. The kid at the pool store said to use 2cups and I honestly wasn't thinking clearly about the wet volume vs dry volume conversion.. I now use 16oz (1/2 a bag). I have an offline chlorinator which I use 4" tabs. I forget what type of chlorine they are. I get them from Anthony Sylvan. Lines have been checked and everything is seemingly working fine. I run this at 5.5 feed with a max of 7 available on the chlorinator. I did the bucket test a long time ago and have not done one this season 1) weather has been very mellow here 2) I knew I was loosing water through multiple channels. Here are my latest chems: ppm
FC: 9.48
TC: 9.48
Combined Chlorine: 0
Ph: 7.9
Hardness: 276
Alkalinity: 84
Cyanuric Acid: 75
Copper: 0.2
Iron: 0.1

Since that reading (wed) I added 16oz less iron, and 4lb ph down. Then I needed to add water in a major way so I didn't follow through with alk+. I have well water and ran hose all night, added back aprox 2.5" of water while pump was off. I was told at some point that for my size of pool I should be able to add @ 1" an hour. Which tells me I'm loosing as I'm gaining I will post some pictures shortly. My equipment pad is dry. Oh and normal psi is 20- 22 which seams high. Thanks again!!

 

[4Season-house]

I just went out to pool. Pump was on and now skimmer (closest to equipment, and one I normally use to vacuum) was pulling air in. This was above the normal level two hours ago. The other skimmer is the one that tends to run at a lower capacity. Also turned pump off. And took some PH dye to do a leak test @skimmers and return lines. All sat relatively still ie no pulling into lines, but dye seemed to pull clockwise. I think my issues have gone from bad to worse...

 

[zea3]

You will need to complete the SLAM process to kill all the algae and clear it from your pool. For a 60 sqft filter you should be using 36 ounces of Purifiber. That is probably why you are seeing algae shoot back into the pool. If you have regular DE I would go back to using it during this process. For DE use a pound per square foot, so 6 lbs for your filter. DE filters very well, is relatively inexpensive, and your filter will need to be cleaned frequently during this process. Possibly a couple of times a day in the early stages. DE filters clog quickly because they are great at what they do, which is catching very fine debris.

Your CYA is too high. Target range for a non-saltwater chlorine pool is 30-50 ppm. I'm estimating your pool holds around 32,000 gallons of water, so to lower the CYA you would need to drain 33-50% of the volume of the pool and refill to reach the 30-50 ppm range. Stop using the tablets. Each one contains CYA that builds up over time. Granulated chlorine sold as "shock" also will contain CYA (dichlor/trichlor) or Calcium (calcium hypochlorite). You should switch to liquid chlorine, either from the pool store or plain unscented bleach from the grocery store. Liquid chlorine will not add CYA or calcium to your pool. Normally using as much stabilized chlorine as you do would lead to much higher CYA levels. Your leak and frequent water replacement has kept your CYA from climbing any higher. You should drain and refill before starting the slam process. This should also help get your copper levels down. I am assuming you used a algaecide containing copper at some point that added it to the water.

Since you need to drain anyway, one way of locating leaks is to let them leak out until they stop. Once the water is lower than any opening in the pool (returns, skimmer, light niche) it is safe to assume the main drain is the culprit if you don't see any other possibilities such as a major crack in the pool shell.

You will need to order a high quality FAS/DPD test kit such as a Taylor k2006 or TF100 to complete the slam process and maintain your pool once it is clear.

 

[zea3]

Is the main drain plugged or is it shut off with a valve?

 

[4Season-house]

the previous owners disclosed at the beginning of this season that @25-30 years ago they made efforts to replace the main drain. I do not know if it was closed prior or if it was having issues at that juncture. In any event durning this renovation process they hired a co to dig a trench to add a piece to the lines. Long story short the Co got stuck and needed a crane to get the equipment out. Therefore the previous owners were not confident that the bottom line was not damaged. They said there is a catch basin where the main drain valves are buried. They sent me a schematic of the location of this.

After that they added a circumvented PVC system. It runs from the pump under the decking and then over the coping down to the main drain. We were told both by the inspector and the company that closed last season that this line was not necessary and that there was adequate circulation; thus had it removed. I was going to add it back but then there seems to be bigger issues occurring.

The diver I had come out at the beginning do the season said that the main drain was plugged and that the hydrostatic floor plug is painted over.

To give some updated stats: I shut off the pool yesterday once I received your message, figuring lets see where this water level drops. So far, I've lost 1.5" in almost exactly 24 hours. It seems like I am loosing more water when the pump is on?!?!? When I told the pool Co I'm now dealing with, of yesterday's water loss from filling over night, they suspected the main drain separating from the pod.? But wouldn't I be loosing more water? Thanks for your help Zea3! What do you think I should do next?

Even with the filter being back washed and clean.(water running clear) could too little de or purfiber cause algae to come back in the pool? What images would be usefull?

 

[zea3]

Pictures are always helpful! There may be a crack down at the main drain, the plug could be lose, or the leak could be elsewhere in the plumbing. Its kind of hard to say. One thing you can try is squirting some food coloring near where you suspect a leak (with the pump off) and see if the food coloring is pulled into the suspected leak. If so that is the location of the leak.

If there is not enough filter media (DE or purifiber) the filter element will not be coated correctly and may allow dirty water back into the pool.

 

[Andrew69]

As Zea says, Id let the water level continue to drop until it stops losing water (if at all)

Sounds like it could be a combination of leaks so the only way to solve it will be by a process of elimination.
Id start with the plumbing first. Let the water level continue to drop until its below all plumbing. If the level stabilises youve got your answer. If not, keep on looking.
Either way, once the water level has dropped low enough, you can pressure test the plumbing lines

However, if the previous owner has already commented on the possiblity of damage around the main drain, you can almost guarantee its going to be a factor

Good luck with it. Chasing leaks is always frustrating

 

[4Season-house]

Hi Zea3. Frustrating indeed. That's exactly what I'm doing. In the first day I lost 1.5" of water.. Each consecutive day I'm loosing @1". Pretty evenly losing 1/2" over night and 1/2 through the day. For ****s and giggles I'm going to do an evaporation test since it's not 'that' much water. And for now since in draining some water it will be with pump off.l I just might be l loosing more when pump is on. I am suspicious of it being the return lines as these pipes (I was told) are of an older material ( black piping) that is no longer in use due to it deterioration factor.

I'm not sure if this means anything, but the water is now past the skimmers. The skimmers themselves are still holding water, albeit very slightly above the basket rim line. Is it safe to rule this out as a leak source?

I've read somewhere that American leak detection was a good source for servicing a pressure test. The technician through my pool place is quoting me $550.00 which seems excessive?!? Any experience on what a pressure test should cost? And where should my water level be for the test? Plenty info on equipment used, but not for preparation of..
Thanks again! This site has been a tremendous resource!

 

[zea3]

I think the price of leak detection tends to vary by region. Hopefully some folks in your general area will chime in on their experiences with leak detection services. Sounds like the skimmers are ok, so far.

 

[4Season-house]

Hi I'm back again. Long story short took the water line down 8.25" at the end of August when I had to do something about the algae over growth. At this point I was only losing 1/4" a day. Filled it back up and I started the slam process. several days later I was cleared. I added back the circumvented main drain PVC pipe line which has helped to keep the flow in the pool. Someone from the company I am dealing with came by to help with the process.. And found it strange that the skimmers were both on the deep end and the returns on the shallow end directly parallel to each other. I hadn't given it a thought until she mentioned it. All was fine for several happy swimming weeks.. Then last week all of a sudden (everything up and running) I had about 3 inches in one day. Since the. I have been filling he water daily to 3" down from the top of the tile,line to only then be at 4.5" down from top of tile.. It makes no sense.. How could all be fine again then suddenly not... I believe I might have gremlins.. Any insight?!?? My pool place is baffled! Thanks!