Any fish you add to a CO2 injected tank will breath faster once CO2 is switched on, any fish introduced to new tank will also breath faster for some time as its a new tank. Fish can take a few weeks to a just to higher [CO2] some faster than others, if their gasping at the surface then they are starting to struggle, if they get over excited in high [CO2] they may go belly up, I had some that use to go belly up when I fed them during main CO2 period so I fed them when main CO2 period was over, the same fish was always gasping at surface during main pH drop then fine once pH drop was over.
If the [CO2] get too high everything will be at the top off the tank snails the lot, too high and you could lose them all.
BPS isn't an accurate way of measuring the injection rate, its more of a means of allowing a little method for adjustment.
Here short vid of my injection rate
2-3 BPS isnt a high rate of inject for a 100l tank by any means.
Looking at the pics of your tank I think the positioning of your filter and powerhead could be improved to give better flow, getting good flow in a CO2 injected tank is critical to success and the plants should be gently swaying in the flow it the tank. I think the powerhead above the filter (if it fits) would work better or the filter and powerhead working together. CO2 diffusor under the powerhead, when you have it right the CO2 bubbles should go to the other side of tank and then go down to substrate level, for which you will need good flow.
Take the air out or only use at night as it will drive off CO2
Ignore the pH chart it wont make life any easier, do a pH profile, take pH before CO2 on every 30 mins till CO2 off and at lights lights on. pH should be stable from lights on till CO2 off, I class stable as same pH +/-0.1pH. getting a stable pH is hard but key to sucess.
Your photoperiod seems a bit long, 5-6 hours should be plenty until you have the algae under control and plants are filling in.
Your plant biomass is a little on the low side so a few floating plants will help short term and help control the algae also.
it normally takes 2-3hrs to get a decent pH drop, only rarely with duel injection does a user manage to do it faster.
The DC colour change you have is fine, however it is the [CO2] in the past (about 2hrs earlier) but using a pH profile along with the DC colour is all I use.
Adjust the injection rate until you have a stable pH
FIRST then DO not adjust it again, just time how long it takes to hit your target pH the time it takes is the time it takes, adjusting the injection rate to decrease the pH drop time will mess up the stable pH. If you are using a duel injection with twin timers and solenoids it makes life easier- but few folk use them due to cost.
I would not use TNC lite even if I had excess NO3 or PO4 in my tap water. I would use TNC complete as its the same cost and the weekly 50% WC will take care of any excess nutrients. With a 100l tank I wouldnt use TNC complete either due to cost. Going down the DIY route will save you money and have more control
APFUK do a starter kit which will last you years for about the same cost of a litre of TNC
