If things were going along pretty good before, and you do not do water changes often, why did you add the CO2?
Plants will grow faster. This will cause more nutrients to be used up. This means either you need to add the correct amounts and test often to balnce the removal rate.
Or do frequent large water changes.
I liken not doing water changes to not flushing your toilet while several of the family members live for a year in the bathroom. Sounds sick but it's sort of what's being done to the fish. Some export is done with the plant pruning but not that much.
Using a python makes water changes a snap. Takes me 45 minutes to change 3 tanks around 125 gallon's worth and I don't life a bucket.
Non CO2 enriched tanks are much more suited to few water changes and general neglect.
But adding CO2 changes things around. Now you are going to need to do water changes or else try a rather impossible balancing/testing routine.
The deal with water changes is that you prevent overdosing or having levels of nutrients TOO HIGH and you also will need to add nutrients to prevent them from getting TOO LOW.
Sure you can try to precisely balance 5 to 17 variable and test for each but virtually everyone fails. Water changes re sets the tank and is much easier.
If your tap water is KH 2.6 I'd just leave it alone if you plan on doing water changes and using CO2. Add enough CO2 gas(don't add anything else to adjust pH) to lower the pH to 6.4.
Keep it there during the lighting period.
You'll need to buy the macro nutrients and you likely have the traces already, eg Flourish, TMG, Sera etc.
KNO3,-stump remover aka potassium nitrate N
K2SO4 sulfur of potash, potassium sulfate K
KH2PO4- Potassium (mono basic) phosphate P
NPK-those numbers of the sides of fertilizer bags.
These are cheap and easy to add. You can get to within 1ppm by dosing them dry, like adding baking soda 1/4 teaspoon etc.
You can get all these from
www.litemanu.com or the KNO3/ K2SO4 from a nursery.
If you add the CO2 you will be growing the plants much better/faster and you'll need address their needs more than you did in the past.
If you don't add NO3 or K etc, you will get stunted plants and when that happens you will get algae.
But here's some good news: 360w of light on a 200 gallon.
This means you'll have much less trouble trying to keep up the balance. At higher light levels dosing becomes more frequent.
But you should still plan on doing decent sized water changes once a week.
50% or so. You don't need to vacuum etc, just remove the water.
Make this easy on yourself.
But I think dosing once a week would be just about right. So after a water change, add the nutrients and then you only feed the fish for the rest of the week.
A drain and fill hose will make the water change thing way easy.
At this light level the plants will grow quite nice with CO2 and good nutrients.
Not too fast.
I would not change your substrate nor your lighting set up with out planning on more trimming of plants and 2x a week dosing etc.
If you use the CO2, do the water changes, add weekly after water change:
KNO3: 1.25 teaspoon
K2SO4: 2 teaspoon
KH2PO4: 1/8teaspoon
Traces/iron: 40mls
Get that CO2 going right first. Keep that level in the 20-30ppm range.
See the pH/KH/CO2 table here:
www.sfbaaaps.com
Regards,
Tom Barr
