High pH 2 part recipe Part 2 lowering alkalinity and dissolved container.

[BoredNuke]

Okay so I have no clue what happened but I initially made a batch of "New DIY 2 Part Recipes with Higher pH Boost". Alkanity mix was with ~280 grams of sodium hydroxide and ~69 grams of Sodium sulfate Mixed with ~1 gallon of RO/DI water in a poly-carbonate container. Made the initial batch and labeled required amounts on container to aim for consistency on next batch. Everything worked fine and was dosing ~50-75ml per day (to make adjustments to kalk water top-off different evaporation rate). After initial batch was used up mixed up a another batch with using same mass/volume (I think..maybe scale was off?) and upon introduction to system (same rate) Alk dropped from 11 dkh to 5 dkh in 1.5 days and a pH spike from normal 8.0-8.15 to a peak of 8.5. Actually started slow decrease and I upped daily additions thinking it was a weaker batch which just made the problem worse. later on the second day notice a leak around the reef control cabinet/dosing containers and found brittle cracks spider web in poly-carbonate container. removed and dumped container and reverted to baked baking soda mix for alk supplementation. I did notice some "snowflake"/precipitation in the high pH mix when I dumped it. I am assuming my scale messed up and way too much Sodium Hydroxide was added resulting in a high pH reaction and dissolution of the container and the container material binding with all the available alk but leaving a high pH solution.
So after all that my real questions are is that a reasonable assumption of the container reacting and binding? And is this a recipe that just needs to be in a glass container due to the >14 pH and I just got lucky through the first batch? Really trying to determine where I messed up as I assume if the container cant handle the high pH then neither can the dosing system but very much liked the results from the first batch .
As always super appreciate any and all advice.

 

[Reefing Madness]

@Randy Holmes-Farley

 

[Randy Holmes-Farley]

Okay so I have no clue what happened but I initially made a batch of "New DIY 2 Part Recipes with Higher pH Boost". Alkanity mix was with ~280 grams of sodium hydroxide and ~69 grams of Sodium sulfate Mixed with ~1 gallon of RO/DI water in a poly-carbonate container. Made the initial batch and labeled required amounts on container to aim for consistency on next batch. Everything worked fine and was dosing ~50-75ml per day (to make adjustments to kalk water top-off different evaporation rate). After initial batch was used up mixed up a another batch with using same mass/volume (I think..maybe scale was off?) and upon introduction to system (same rate) Alk dropped from 11 dkh to 5 dkh in 1.5 days and a pH spike from normal 8.0-8.15 to a peak of 8.5. Actually started slow decrease and I upped daily additions thinking it was a weaker batch which just made the problem worse. later on the second day notice a leak around the reef control cabinet/dosing containers and found brittle cracks spider web in poly-carbonate container. removed and dumped container and reverted to baked baking soda mix for alk supplementation. I did notice some "snowflake"/precipitation in the high pH mix when I dumped it. I am assuming my scale messed up and way too much Sodium Hydroxide was added resulting in a high pH reaction and dissolution of the container and the container material binding with all the available alk but leaving a high pH solution.
So after all that my real questions are is that a reasonable assumption of the container reacting and binding? And is this a recipe that just needs to be in a glass container due to the >14 pH and I just got lucky through the first batch? Really trying to determine where I messed up as I assume if the container cant handle the high pH then neither can the dosing system but very much liked the results from the first batch .
As always super appreciate any and all advice.

Bad move. Polycarbonate is not stable at high pH.

Most plastics are fine. Polycarbonate is not.