Fertiliser question

[KD1992]

I'm new to using CO2 and fertilisers so please go easy on me

I've had my 340l set up since January 2023 so just over a year, I live near Sheffield, UK and I'm with South Yorkshire Water. My tap water is

0 ammonia
0 nitrites
0 nitrates
PH around 7.3 (tested with liquid test kits and PH pen)
GH 2
KH 1 or below

Test results from my tank are

0 ammonia
0 nitrites
0 nitrates
PH drops to around 6.9/7
GH 3
KH 1 or below

My substrate is sand with fluval stratum underneath in mesh bags. I'm using a Fluval FX6 with biohome ultimate. I test my water a couple of times a month and I've never seen any ammonia, nitrites or nitrates. my light is a Chihiros WRGB2 Pro 120 and I've recently added a DIY CO2 reactor and I'm getting a dark green drop checker through the photo period (I'm working on getting the drop checker brighter).

So to get to my point, I'm wanting to start using a liquid fertiliser but I don't know if I should be buying a fertiliser with phosphorus and nitrogen or not. Most of my plants are Crypts, my Cryptocoryne Balansae is exploding with growth but my Willisii and Lutea don't seem to be growing.

I was going to buy Tropica Specialised nutrition but I don't know if I need to be adding nitrogen and phosphorus or not

 

[hypnogogia]

I was going to buy Tropica Specialised nutrition but I don't know if I need to be adding nitrogen and phosphorus or not

Yes, you should be adding N and P. I wouldn’t trust the measurements with home test kits, but as you’re using CO2, you need to add an NPK fertiliser. Tropics Specialised is expensive, you’d be better off using something like TNC complete or, if you’re willing to try and use the fertiliser calculator from UKAPS, mix your own by buying the necessary salts. By far the most economical way of doing it.

You also need to increase your CO2, aiming for a 1pH drop.

 

[KD1992]

Yes’m you should be adding N and P. I would trust the measurements with home test kits, but as you’re using CO2, you need add an NPK fertiliser. Tropics Specialised is expensive, you’d be better off using something like TNC complete or, if you’re willing to try and use the fertiliser calculator from UKAPS, mix your own by buying the necessary salts. By far the most economical way of doing it.

You also need to increase your CO2, aiming for a 1pH drop.

I was looking at TNC complete, it is a lot cheaper. And the problem I'm having with my CO2 is there's too much flow through my reactor, if I increase the bubble count then I get big bubbles escaping the reactor. I did originally have an Eheim Compacton 3000 pump powering my reactor with a ball valve on the outflow but it was making too much noise so I changed pumps to the TMC Reef Connect 2500 and broke the ball valve so I need to order a replacement

 

[hypnogogia]

Ps, forgot to say, check your water report for NO3, GH and Kh as that will give you base levels and help you to work out how much fertiliser you’ll need and also what type of chelated iron.