Almost 4 months to the day since we got our hot tub (J-385 500 gallon). Water has been crystal clear the whole time with no issues.
Sunday we did our weekly testing and filter rinsing (we clean the filters and change them with a clean set every 4 weeks) with the following numbers. We use Nature2 with Leisure Time Replenish (and MPS + other "stuff" product) tho sometimes we use straight up Dichlor depending on what we reach for.
Water was crystal clear during testing. We run the circ pump 24/7
Using the MPS test strips:
MPS - Low (not entirely unexpected, hadn't been in in 3 days and didn't add anything to it)
Alk - 100
pH - 7.2
Using the Taylor test kit:
FC - 0.6
CC - 0.2
CH - 110
Alk - 70
pH - somewhat between 7.0 and 7.2 on the color scale so a TOUCH low but I figured it was due to only the circ pump being used in the last 3 days and I thought jets running would stir it up and raise it so I wasn't concerned)
CYA - 70
I know the CYA is getting high after 4 months (we don't do the dichlor then bleach method but may switch to that with the next fill). We figured we'd be draining at least half the water in the next week or so, if we didn't just opt to do a full drain and refill since it's been 4 months.
So anyway, I tossed in a bit of the Replenish to get the MPS level up a bit and we closed it up.
This week has been busy but we went to go in last nite and the water was completely cloudy. So bad you could barely see the foot jet dome. Our Nature2 cartridge is 4 months old so I suppose due to be changed and I'm wondering if it finally just lost enough (tho the grains don't go away, so how do you know when it's used up??) to not be able to keep up with just using Nature2 and MPS?
The Taylor kit book says for algae bloom, take it up to 30ppm FC so I put in enough dichlor to take it up to that and ran the jets for 40 minutes. My husband thought it looked a little better. Looked at it this morning and I can see the back jets (only took the cover half off because it's freakin' snowing here right now!) so that looked a bit better to me.
Do we just let it go for 24 hours or so and see if it cleans up? Of course now our CYA will be really high so we definitely need to take out at least most of the water soon but I ordered some Ahh-some which will be here Saturday since we didn't do that on initial fill so I'm thinking we'll drain, fill, ahh-some, drain and fill again and then balance the water but any ideas on what prompted such a fast change in the water? I'm wondering if it's because the CYA is up so high that we didn't have the FC up high enough to compensate (if I have that right, I think the chlorine becomes less effective as CYA rises so you have to use more dichlor to keep up to raise the FC high enough). But I'm surprised it happened so fast. No algae on the sides or anything, just generally REALLY bad looking water, very very very cloudy.