re-filling nearly empty pool with algae on the bottom

[quick89]

Hello,

We have an oval 30'x15'x5' pool with a cartridge filter. Last year we started using the BBB method and had great success. Over the winter we did not have a cover and ended up with a very nasty pool now. Yesterday we reinstalled our filter and turned it on to start the process of opening the pool. Since our water level was low we connected our vacuum hose and head to the filter so that it would draw the water through that. Sometime overnight the return line on the filter popped off and we ended up draining the entire pool, leaving only about 6 inches of water in it!

So, unfortunately, we solved our nasty water problem. However, there was still a nasty "carpet" of algae on the bottom. We attached the vacuum hose and head to the filter and disconnected the filter return line and removed the filter. This basically led to us sucking up the algae "carpet" and shooting it onto our yard by the filter... which is what we intended. We got about 75% of it out, there was still a small amount of algae on the bottom but it was getting late so we stopped.

We have now reattached the filter and filter return line and have it sucking water through the vacuum hose and vacuum head and shooting it back into the pool. Essentially, we are now filtering the remaining 6" of water in the pool. I dumped 4.5 gallons of 6% bleach in there as well. We have also put our garden hose in the pool and are filling it with our city water.

As the water level increases I will be testing it regularly and am hoping to bring all the chemical levels up to their proper levels. Is this the right strategy moving forward? I'm hoping that the super high levels of chlorine added today will kill off the remaining algae and that the filter will get all the dead algae out of it. I intend to regularly check the filter and clean it as necessary during the filling process.

Thanks in advance!

 

[JasonLion]

Welcome to TFP!

Using that much chlorine all at once in a mostly empty pool isn't so good for the liner. The FC level will have been very high and that could have caused the liner to fade where there was high FC water water or have shortened it's lifetime somewhat.

As long as you have the pump running and circulating the water, then that all sounds good. One thing to keep in mind is that the CYA level is going to drop quite low as the pool fills up, and you are going to lose all of your chlorine to sunlight as the CYA level goes down unless you start bringing CYA back up fairly quickly.

Keep an eye on the FC level. You may need to do a little more shocking of the pool once it is full again. It depends if any of the algae you missed with the vacuum is still alive or not. It is probably all dead at this point, but just in case watch for FC suddenly dropping.

 

[quick89]

Thanks for the quick and insightful reply!

 

[quick89]

The pool completed filling up and has very nice looking clear water! About 99% of the algae on the bottom is gone except around the very edges where our vacuum head cannot get. Any ideas on how to get that off? I was thinking of using a brush to kick it up into the water and off the liner and hope that the filter could get rid of it.

 

[JasonLion]

Yes, brush it up and either the filter will catch it or it will settle somewhere else where you can vacuum it later.

 

[woodyp]

Yep............just brush it.