Test Results after Water Replacement

[smccray]

Was hoping to limp through the summer with my water as is, but sadly my numbers before were pretty bad. I replaced approximately 60% of the water in my pool. Now I'm refilled, dumped DE into the filter, and I'm watching the water.

New test results, assuming I'm doing the tests right:

FC 7.5 (raising to 10)
CC 0
CH 400
TA 140
CYA 90
PH 7.5

The good news is that the water is clear. I can easily see 8' down to the drain. The bad news is that the water has a bit of a green tint. Fortunately it's largely overcast today- I'm keeping an eye on the water. The water has cleared up a bit (less green tint) over the last hour, so we'll see what happens. I'm anticipating a SLAM coming here pretty quick- going to take 11 gallons to raise me to 35 PPM at a CYA of 90. Given the green tint I would expect CC to be greater than 0, but I'll just have to test again later this afternoon.

I estimated that my CYA prior to the water replacement was 120, but sadly that couldn't be the case the CYA today. I didn't attempt to dilute the pool water to better estimate the CYA pre-water swap, but oh well. I suppose I wish I would have drained just a little more water out of the pool, but oh well. I'm not going to do another water replacement, so we'll just see how it goes this summer with a CYA of 90.

Stenner pump is in hand and almost ready to install. It will probably be this weekend before I get it up and running, but that's probably a good thing- I'll be able to learn the chlorine usage over the next week.

Pool is a 35K gallon in ground gunite/plaster pool & spa with a 48 sq ft DE filter.

 

[zea3]

A slam with 90 CYA is do-able, it will just take a lot of bleach and diligence. Once you get to slam level check the FC every couple of hours and brush the pool daily. When your slam is complete be sure you stay at the top of your target FC range.

 

[smccray]

I performed a FAS/DPD test about an hour after I added 1 gallon of 10% bleach. I expected a FC rise to 10.5 based on a 35K gallon pool. I actually saw a FC of 11.5 which is more inline with a 26-27K gallon pool, which means a SLAM will take less bleach. CC was still 0.

Water looks better this afternoon, but the green tint still isn't out of the water. If CC is still 0 tonight, does it make sense to watch the water before slamming? Any chance I have metals or something else in the water giving it this tint? Is it possible to have an algae bloom without CC showing up in the test?

Edited to add: going to perform an overnight lost test tonight.

 

[jblizzle]

Either the pool is not 35k or the bleach was a little extra strong ... it is impossible to be exact. Just keep track over time and see if you are consistently off and adjust the volume as needed.

It is VERY possible to have algae with no CC ... that is why there are 3 criteria for stopping the SLAM process.

 

[zea3]

What color is your plaster? Do you have any reason to think there may be iron or copper in your pool? If it is cloudy and green then that would be algae. Clear and green might be metals.

 

[smccray]

What color is your plaster? Do you have any reason to think there may be iron or copper in your pool? If it is cloudy and green then that would be algae. Clear and green might be metals.

Any reason? I have a pool guy... he dumped some **** into the pool a couple weeks ago before I had adopted the BBB method. I don't have a clue what it was, and conversation with the pool service is coming tomorrow. If they're not willing to supply my stenner pump tank with liquid chlorine then the benefit to those guys is pretty much gone.

I raised the FC to 35 per pool math assuming a 26K gallon pool (6 jugs!). I'll give it an hour then test to confirm that the the FC level is 35. Then I'll test again in the morning and we'll see what happens. With any luck the overnight loss test will be inline with expectations and we can at least rule out a pending algae bloom. DE filter is good to go as of this morning so I'll keep an eye on the pressure in the morning.

On another note... is there an easier way to test the FC level than to use all that reagent? Perhaps diluting the pool water 3:1 with reverse osmosis water then multiplying the result by 3?

 

[smccray]

I tested the water last night before bed and determined that I needed one more jug to raise the FC to 35. 7 total- wow.

Pool passed the overnight loss test. CC was zero last night and this morning. Water is clear. It looks a little bluer than yesterday, although it's sunny this morning compared to overcast yesterday. Not sure how the change in the light impacts the color of the water. I'm planning to let the FC drift down unless someone here suggests otherwise.

I don't love the color of the water, but will a little bit of metals harm anything? Pool doesn't get a ton of use and we're remodeling the pool this fall.

 

[jblizzle]

Have you added any sequestrant?

 

[smccray]

No- the only thing I've added to the pool is chlorine. Need to do some research on sequestrant.

Seems a little odd to me that I'd have high metals given the amount of water I just replaced unless the fill water has high metals. I suppose it's possible that the pool guy added that much algaecide a couple weeks ago. I found a 3 year old report on Plano, TX water that says copper is below 1.3. I suppose that could have changed, or that the 20 year old copper in my home is adding a lot of copper into my water, but it seems unlikely to me. Who knows. Going to research sequestrant

Thanks for your continued support!