Recommendations sought for balancing my tub at start-up

[DangerBoy]

Will soon be doing a fresh fill on a new (to me) used fibreglass hot tub. Here's my starting water chemistry:


CH 160 mg/L as CaCO₃


TA 114 mg/L as CaCO₃


pH 7.8


Free Chloride leaving the water treatment plant is at 1.1 mg/L so presumably >1 when it reaches me.


Is the CH of 160 close enough or should I try to somehow lower it to at least 150 or less? If best to lower it, how should I go about doing that?


I understand the process of lowering pH to ~7 and aerating to raise pH and lower TA. Given the CH of 160 mg/L or whatever I can lower it to, what final TA concentration should I be shooting for? 60 mg/L?


TIA

 

[kimkats]

Pool School - Recommended Levels basic link to water levels.

How do I use Chlorine in my Spa (or pool)?) a good write up for spas.

You also need to get some ahh-some to clean out your spa. Here is a write up about it. Ahh-some goes head to head with oh yuk

 

[jseyfert3]

Usually about 50 ppm TA, BUT, it varies slightly. The real goal is no pH rise, so once you get your TA near 50, aim for a pH of around 7.5. Once you get a stable pH in this range, your TA will most likely be somewhere around 40-60 ppm.

 

[DangerBoy]

The Pool School and How do I use Chlorine in my Spa (or pool)? articles provide some conflicting information. For Fibreglass, the Pool School article says CH should be over 300 whereas the other article says its fine if it's over 100 and 100-150 ppm is preferable. Why such inconsistency there??

160 is not far off from 150 so I think I'll leave it there. The problem is our water gets up over 200 ppm during the winter months so I'll get a rise in hardness any time I add some water to the tub to keep it full.

 

[jseyfert3]

In general we don't typically worry about CH much unless you have a plaster/stone/gunite pool. I'd just leave it where it is.