Newly Opened Pool Turned Cloudy
Some background. 18,000ga gunite pool with a sand filter with brand new (300#) sand and rebuilt pump. We bought the home in January with no pool history, only a loop-loc cover in place with pool filled to closing levels. Decided to hire someone to open the pool since I had no clue where the plugs were or how the system was piped or if the sand was good. When the cover was removed there was a lot of sediment on the floor but water was clear with with greenish tint.
We live in a very windy and sandy area (desert) but despite that the pool guy thought it hadn't been opened in at least a season or two. It appeared to have been closed correctly. A portable pump was used to vacuum the sediment and the pool was brushed and skimmed. The sand in the filter was very white and replacement was recommended and done. 8ga of liquid chlorine was added along with 2 bottles of Algea-X and 1 bottle of Sequa-Sal. Pump was started but would not prime. Rebuild was suggested and was found to have a gasket inserted backward and corroded motor mount bolts requiring a new motor unit. Was picked up a week later (pool not circulating during this time but was clear with a lot of white sediment at the bottom) and started up.
Water testing at that time was TC 2.0, Alk 200, Ph 8.0, Ca 190, CYA 60, TDS 760 and was recommended to add 3ga of muratic acid. This was done and water has been circulating for 12 hrs a day with a Polaris sweeper running for 5 days. At the addition of the muratic acid, the water clouded up and has remained cloudy since. I have backwashed the filter twice upon pressure readings. Today I brushed the walls and steps (a fine dirt sediment likes to settle on the steps) and took in another water sample to a different but closer pool supply store with readings of FC 3.0, Ph 7.4, Alk 120, HRD 200, CYA 10 (not sure about this reading), Phos 2000+ and was recommended to add a phos remover. I had seen your youtube videos and opted to not purchase and decided to seek your assistance.
Ideally I would not like to drain and fill the pool (I have a well). My kit is limited in usefulness and I got a reading of Ph at 6.5 and CL of .1. I plan to get the one you recommend. Should I add more liquid CL to shock more or do I just need to give my filter more time given the new sand? Also, I have a clorinator tower with the 3" pucks in it. Not sure how I feel about that given the initial high CYA read but it was part of the system when I purchased. Thanks for any insight you can provide.
Thanks for the question Jennifer and it's great that you watched some of my videos.
First we'll start with the filter. New sand can take a couple of weeks to settle. It has alot of fine dirt and debris that will go through the laterals, through the returns and settle to the bottom of the pool. This is normal. The only thing you can do is to vacuum it up. Next is to be sure you have enough sand in the filter. This is called freeboard which is the measurement from the top of the sand to the top of the filter. The new sand will settle when it gets wet, leaving a larger gap between the two. Check your owner's manual for the right amount of freeboard or you can call the filter manufacturer. You may need to top it off with a few inches of sand.
Next are the readings. Everything but the CYA is very easy. Little acid or bicarb, shocking the pool, and you're finished. But it's the CYA that throws alot of pool owners. First thing is to be absolutely sure what the reading is. 60ppm is totally different than 10ppm. A higher CYA and you'll need to do a partial drain and refill. Lower CYA is fine. Just add 1 lb. to increase 10ppm per 10k gallons. That's it. I've made several videos on the importance of the CYA. I have 2 sets
of videos demonstrating how to clear up and balance a pool. One pool had a CYA of 100 so I drained 2/3 water and refilled. Another pool had no CYA so I added some, then cleared it up and balanced out the chemicals. Two totally different approaches to a green pool. Get the Taylor K-2006 kit and watch my videos on how to use it. I go into great detail.
Algae X is a copper algaecide which you DON'T want to use if you're on well water. You probably have high copper/iron. Adding more copper will cause more problems such as metal staining and possible foaming. If you want to use an algaecide the only one is a PolyQuat 60. No metals and safe for vinyl liners.
Next is Sequa-Sol Metal Scale and Stain Remover which is sodium citrate, part of the phosphate family. It's basically sodium salt. You can Google that if you wish. Another product you don't need unless you have metal staining. If you do there's a cheaper alternative. It's ascorbic acid which is nothing more than crushed up Vitamin C. That's an entire process in and of itself but we'll cross that bridge later. Again if you don't have metal staining then you don't need it. I do recommend a metal sequestant. Metal sequestrants that are based on HEDP, phosphonic acid and/or its derivatives are the most effective. Some popular brands are Jack's Magic Blue, Purple, and Pink Pink Stuff, Metal Magic, Metal Free, & Metal Klear. This is normally not a one shot deal. A metal sequestrant does not remove metal from pool water. It holds it in solution until it can get filtered. Then you backwash the metal out. Because metal sequestrants break down over time and get filtered and backwashed out, you will need to add a bottle once per week.
So to sum it up, you need to know the CYA level. Too high = partial drain and refill to get to 30ppm. Too low = add some to get to 30ppm.
Once you have that in place you'll need to shock the pool a few times with liquid chlorine. The pH and TA seem to be fine right now. You want a slightly lower pH while you shock. Use 1 gallon to increase the FC 10ppm per 10k gallons. Shocking is a process, not an event. The trick is to get AND keep the chlorine above 15 ppm for a period of time. You'll need to manually dose the pool with chlorine to keep it at 15 ppm. Make the adjustment at night, then retest in the morning. Be sure to have the pump running 24/7 and backwash once per day. You can go up to 15ppm, but no higher. Anything after that and you're wasting money and chemicals.
You'll know this is working because the pool will go from green to a white/grey cloudy and the chlorine will begin to hold better. First you may lose most, then 2/3, then 1/2, and so on. Once you only lose 1 - 2ppm of chlorine 8 - 10 hours after the last application you know the algae is dead. Now it's just a matter of filtering and backwashing once per day. Broadcast the chlorine around the perimeter of the pool and brush well. This will loosen up any algae adhering to the walls and bottom.
Shocking a pool isn't adding a bag of chlorine to a pool and expecting it to clear it up. Shocking a pool means to kill/eliminate the algae and organic matter. This is done by dosing the pool with enough chlorine to reach a high enough FC level and keeping it at this level to allow the chlorine to kill the algae and organics in the pool. You're in a race to kill the algae faster than it can reproduce. Most green algae can reproduce, mature, then reproduce again within 5 hours. Over a 24 hour period that's almost 5Xs. Think of the trillions of spores that are doing that. That's why you must keep the FC up to 12ppm by super chlorinating morning and night.
Don't worry about the phosphates or phosphate removers. They're pretty much useless for weekly maintenance. The only time you'd need it is if you had a bag of fertilizer thrown into the pool. They're also very expensive.