~4 month old pool, tested cya in january and it was >30, tested this morning after noticing FC levels being quit volatile for the last few weeks and swg running far too much, CYA seems to be <10 although exact level is hard to tell since it is so low.
Not sure how we could have lost so much cya in such a short amount of time (yes, we do swim alot with small kids that splash out water, but certainly 20 pts of cya in just a few months is much more than natural?)
There's been quite a bit of rain too, but our pool is covered and water normally just stays on the cover until it is pumped off.
One other possibility is that we have a hydrostatic valve which is apparently going up when it rains because water table rises...I find worms/etc near the drain even with cover on. I understand this isn't unusual.
So, I'm wondering...am I overthinking this in thinking we either have:
- cya eating bacteria (don't think so, but just finished shocking pool to verify algae wasn't eating chlorine - water looks crystal clear and CC is zero)
- hydrostatic valve somehow causing leak or introducing additional water that dilutes pool cya?
- other form of leak?
Water level seems relatively stable even when autofill is turned off for several days with cover on. Haven't had any reason to think there is a leak yet...and we had a good plastering company put in pebble sheen.
- Pool builder suggested cover opening/closing might be causing water loss
- However, the salt readings on the ic60 haven't shown any drop in salt over the 90 day period...so we're probably not looking at a leak or normal splashout/evaporation.
Note that I have to keep the cya low at ~30 due to ORP sensor. Perhaps there is also an artifact from the intellichem running the SWG at 100% when needed.