Results valid with 1/2 reagent?

[masscc]

I went to test cya (7.5ml water, 7.5ml reagent) but when I poured the last drops of my R-0013, there was only about 1/2 of the 7.5ml the test calls for. But I went ahead with the test just to see if it registered. I had added CYA a couple days ago estimated to bring it from 30 to 45, (per PoolMath: 20oz-wt CYA for 10k gallon pool) so I was expecting some change. The test with 1/2 the reagent actually showed me to be near 50 now.

So, my question is whether the test is possibly valid, or would it necessarily yield lower results than actual using reduced amount of reagent?

I won't have more reagent 'til next week, so should I dose liquid bleach based on CYA=50 until then?

 

[duraleigh]

Welcome to the forum

That 1/2 strength test is completely invalid. I would suggest you add 5 ppm of FC daily until your kit gets to you.

Post your results here and we can all help much better.

 

[Newdude]

So, my question is whether the test is possibly valid, or would it necessarily yield lower results than actual using reduced amount of reagent?

Did you add half the 7.5 ml of pool water to match the half the 7.5 of reagent ?

As long as it's a 50/50 mix, it's all the same. Smaller amounts make being a drop or two off either way more pronounced, but should give you an idea at least.

If you mixed 25/75 instead of 50/50, you did an unintentional dilution test.

 

[masscc]

No, I didn't realize I didn't have enough until I had already added all of it and it wasn't enough. The mix was basically 2/3 pool water and 1/3 reagent.

I know I had 30 CYA day before yesterday, and I added 20 oz-ish dry CYA by sock on return, day before yesterday.

Currently I'm showing:
FC=6.5
pH=7.9 (electronic)
TA=100, day before yesterday

 

[masscc]

Thanks for the replies.

I'm just hoping I got the CYA add right. I certainly didn't expect 50 since I was shooting for 45, and I suspect my pool is a smidge bigger than 10k. I've only had it a year, and it seems that the result of most of my adds are always just a little under target. I'm not sure yet where I want CYA to live. I see others in high sun gulf area (like Houston) say 55 is good.

 

[Newdude]

I'm just hoping I got the CYA add right

Welp. We'll know when the replacement reagent comes.

 

[proavia]

If you tested CYA at 30 ppm and added 20-ish ppm, you were shooting for a CYA of 50.

Dose FC based on CYA of 50. Even if your CYA addition added 0 (zero) CYA, you would be well within the safe level of FC all the way up to CYA 30 SLAM level of 12.
Just keep the FC within 6-8 ppm (absolute minimum of 4 ppm) - it's still a safe FC range for your equipment and for swimming even if a little high for CYA 30.

Once you get your R-0013, retest the CYA and adjust accordingly.