Water Exchange Question


Well-known member
Oct 16, 2019
The Villages, Florida
I have a new pool, and now that the Wet Edge finish is about 2 months into curing, my Calcium hardness is very high (~900). My fill water is around 175. I'm looking at doing a water exchange to address the issue.

Pool facts:
  1. Pool is saltwater
  2. Pool depth goes from 4' to 5'
  3. Size: 24.5' x 12.5'
  4. Gallons: 6,900
  5. Skimmer is located near the deep end
  6. Autofill is located nearer the center of the pool
I currently own a 1/5 hp Superior pump that connects to a garden hose. Several quick questions:

  1. Can I use this pump, or do I need a larger pump? I assume the use of a garden hose restricts flow anyway.
  2. Should I run a hose into the shallow end, or could I use my autofill since it's a saltwater pool (or both - to keep up with the flow of the water exiting.
Thanks in advance!

FYI - My hardness was around 500, but the Wet Edge finish had an uneven look. The installer did a low PH acid bath and while that corrected the finish (looks fantastic now!), it drove up the hardness quite a bit.


Mod Squad
TFP Expert
LifeTime Supporter
May 11, 2014
Franklin, NC
You are correct, the no drain acid wash basically stripped a layer of calcium off the pool surface. Think of it as them giving the pool a facial chemical peel.....

So, the "best" way to do this would be tor drain the amount of water out of the pool yo want and then replace it. This will keep the new water form mixing with the old. But, this would also expose parts of your new plaster that is normally below the water line to that ice Florida sun.

The next way to do it would be to put your portable pump at eh end of the deep end and refill from the surface of the shallow end. Leave the pool pump off during this procedure to keep the watere from mixing as much as possible.

A third way is to get a really big tarp and cover the pool. You would pump out from below the tarp and replace water above at the same rate. Again, leave the pool pump off during this procedure.

I guess you are getting the picture. The object is to avoid "mixing" of new and old water so you remove the most calcium laden water as possible, but none of these would be perfect in avoiding mixtures happening except the first.