Ever do a flash 50% water change in an emergency?
I keep a 5g water jug on hand in case something gets spilled in the tank and rods of ice in the freezer because the summer tap-water temp here hits 92°. I've never had to use them before but last week the hardness and alkalinity went hard zero and the pH started swinging from 4 to 8 in my community tank. I did a buffered baking soda, pond acid, neutral regulator, pH reducer mix and hit the jug with my hose faucet then dropped in the rods. You have to predict when the temp will pass through the range you want and have the tank drained ready.
Terrifying experience but I couldn't risk adding chemicals to the tank one at a time, it'd have killed everything. As it was I got to count my fish, the shock from hardness knocked all the methane and CO2
out of the soil bed and the bicarbonate chewed up most the free O2
in the tank. Was surreal to see the peat remnants of the potting mix I used for soil releasing fine bubbles. Every fish in the tank headed to the surface to suck on the water coming out of the filters.
Didn't lose a single fish: eighteen mixed tetra, four betta girls, Buck the molly, two guppies. I've a pair of Emperor 280s on the back of it, makes the volume about 10g after substrate. They aerate fairly well, so does the 5g hydro sponge in the end. So I've probably got more than six hundred gph of flow in a nine gallon volume of living space. (Sorority is being sterilized, unknown bloating death that wasn't bacterial, fungal or parasitic.)
The water I put in had a hardness of about 36 degrees... 690 or so ppm calcium carbonate pre-buffered, it came out to about 300ppm mixed and then I cut it with a second flash 50% using the remaining ice in the jug.
My hose tap blows 82psi and will fill 5g in about 14 seconds. So strong I have to wedge the jug in place with my shoe.
24 hours after I pushed the hardness up, most of it had buffered back into the soil substrate again... I don't even have any calcium deposits on the intake pipes.
I'm a keeping a bag of crushed seashells in the filter now.
The plants sure are growing fast!
Just another insane story from some freshwater hack.