advice please - alkalinity issue

[psychonaut]

very hard water here. running bromine in a jacuzzi J480.

trying to get serious about levels and control of the water,

have tried to use ph- but have put 200g in so far and i am at 200 Alk, ph is near 8. i need to get ph down. but cant do that till i get the alk down. calcium hardness is 250. (its very chalky here). the last dose i put in was 100g ph- and the levels didnt change at all according to my titration based test kit. (alk tablet, drop in spa water into measurement jug)

really want alk at 150 or lower.

so i thought i would buy some 10% hydrochloric acid. (muriatic acid).

in the UK, you can only buy at 10% strength unless you have a license, so i have 10% muriatic - at least i think this is what that means, noone has been able to tell me what muraitic is sold as in the USA, ands all the posts relate to USA measurments and products .

i'm reading wildly different things on the internet as to how much i should put in my tub (1800 litres). pool calc says at 15% muriatic i need 75ml, other things i read say many litres.

i need some advice please!

 

[ajw22]

Welcome to TFP.

What test kit are you using?

What chemicals are you using?

Give us some numbers - what is the tap water pH and TA?

 

[psychonaut]

thanks for coming back to me.

pool tester for ph (phenol red tablet based) and lab sales tablet based titration for alk and th - not taylor, but pretty good quality i think.

chemicals - only used ph- so far, from clearwater


tap water - it UK mains water - alk is 3 or 4 hundred or higher, calcium 300 or so, ph is about 8 or just under - this fill i have used an inline water softener, although I'm not sure how much difference it made as the readings I get aren't that much different to what i used to get, possibly i ran it too fast. the previous 2 fills we had calcium dry wall feel on the tub walls straight out of the fresh fill with a bit of ph reducer in it. this hasn't happened this time, so maybe the softener did something. its also possible that the readings were crazy high without the inline softener, and maxed out the kits , giving a similar reading as to with the softener.

so I have 10 litres of 10% HCL (muriatic) in the shed....