[Minsc]

Last year my trusty Filstar finally died. I bought a new canister, but because of some miscalculation on my part, it was too weak for what I wanted.
After several months I only had rotala rotundiflora, anubias nana, blyxa japonica,
and lindernia Indian, all of which were doing well.

I bought a larger canister, and added the bio filtration that originally came from the old filstar. The flow is great. Soon after my plants became very pale on the new growth. The lindernia, rotala, and anubis have bounced back, although the rotala is still pale.
My huge field of blyxa japonica completely melted 😢

The plants really looked like they had a severe nitrogen deficiency.

CO2 should be good. If I turn it up more the fish start acting weird.
Substrate is pool filter sand, I dose EI.

What the heck happened?

I just today swapped out the sand for aquasoil v.2. I’m really excited to have aquasoil again. My tank was so sweet the last time I got fresh aquasoil 🙂

 

[rzn7z7]

I once set aside a canister filter and opened it a week later to find the surface of everything had turned black - without the constant flow of water and the nutrients and oxygen it brings the beneficial bacteria died and I tossed all of the media

Any chance of that occurring here? Any livestock losses?

Else, perhaps the increased flow from the new filter upped plant metabolism and you're experiencing some sort of deficiency, or it stirred up detritus leading to an ammonia spike

What brand of filter is it?

 

[PlantedRich]

One word of caution for all situations in life? When you find yourself in a hole, stop digging!
So you have a problem with the plants not showing their green? Changing the sub at the same time seems to be one way to get even more confusion going!

Some numbers from testing would be where I would start as it is always good to watch closely after any major change like swapping filters.
Did you lose too much good bacteria on the switch and make a mini ammonia spike? Testing was needed but after doing a swap on the sub, it will be difficult to tell which or what the problem may have been.