Pool Math to determine Bromine Levels

cschnurr

Silver Supporter
LifeTime Supporter
Sep 21, 2007
115
Guelph, Ontario, Canada
Pool Size
96000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Hayward Aqua Rite (T-15)
I have a 1350 litre hot tub, sanitize with Bromine and 32% MPS activator (Rendezvous Activate), and my ozonator is not working.
I'm trying to get my head around using the Pool Math to determine how much MPS to add to achieve specific Bromine level.
I think there is something wrong with my thinking, and I would like to get some input.

The instructions on my MPS container states that initial dosage of 125g / 1000 l of water.
Therefore I should put in 170g (1350*125).
The lid has amount graduated in grams.
It takes about 80ml of water fills up to 125g mark, estimate density 1.6 g/ml
So my recommended dosage is 110ml (170/1.6).
There is no mention of the expected Bromine ppm.

However, as per recommendations on this site, I'm aiming have Bromine level of 10ppm at initial fill.
This would be the equivalent of 4ppm (10/2.25) of Chlorine.
From Pool Calculator this would require 42ml of 12.5% Bleach

In a previous thread, I read that for each Bather-hr, the it takes the following amounts to oxidize bather waste.
3.5 tsp (17.25ml) of 43% MPS with Ozonator
7.0 tsp (34.5ml) of 43% MPS without Ozonator
5.0 oz (148ml) of 6% Bleach
2.5 oz (74ml) of 12% Chlorine
So I'm assuming these qty's are equivalent.

So 42ml of 12.5% Chlorine is equivalent to 20ml (42*34.5/74) of 43% MPS without Ozonator
Which is equivalent to 27ml (20*43/32) of 32% MPS without Ozonator.

The amount specified on the container is about 4x my calculated.
 
Last edited:
I found a related post in 'The Deep End'

I think it explains the process to use Pool Math for Bromine, but it doesn't sound very conclusive as it took a couple years to add a correction.
 
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