How long does it take water to circulate?

[littleHeidi]

Is there a formula you can use to find out how long it takes for your water to fully cycle through? I had to backwash this morning and add more water. I tested the cl right after and it was at about 12 (where I need it to kill the algae). About 4 hours later I tested again and it was only 2. I guess what I need to know is when would have the most optimal time for me to have rechecked the cl in order to make sure my level stayed at 12? Thanks guys!

[mas985]

You have to know your turnover to determine what a full cycle will be. Turnover is determined by head loss and your pump curve. However, one turnover of the pool does not mean that 100% of the water went through the filter. It simply means that the same volume of water that is in the pool went through the filter. So, some water goes through twice and some not at all. It takes several turnovers for all of your water to go through your filter at least once.

As to your question, with algae, it is probably good to check every 4 hours or even more often until the chlorine can stabilize and most of the algae is dead. This has less to do with turnover and more to do with how fast chlorine is used up killing algae. You can help the mixing process by pooring in the chlorine in front of a return and using a brush to mix it up.

[littleHeidi]

Aaaaaah, I didn't know that. Thanks! I assumed all the water got circulated through in a couple of hours. I have been dumping the bleach in at the deep end jet and brushing it twice a day. It all keeps settling in the same spots for some reason. Thanks again!

[mas985]

Are you using liquid bleach? If so, how can you tell it is settling anywere? It could be dead algae you are seeing which can be vacuumed up to help the process.

[littleHeidi]

Are you using liquid bleach? If so, how can you tell it is settling anywere? It could be dead algae you are seeing which can be vacuumed up to help the process.

LOL, no the bleach isn't settling in the same spots. The ALGAE is!! Sorry for the confusion. (And yes, I'm using liquid.)