Planted FW tanks, substrate, pH and CO2 questions ..

[Delphinus]

I should ask this on a FW forum but what the heck let's put some activity in this one ..

I have a planted FW tank, must be coming up on 5 years old, and there's something I've never really been able to understand with this stuff.

I inject CO2 to try to have better plants than algae. For the most part it does not work out. For one, I can't seem to lower the pH of the tank .. at all .. with CO2. In fact, the pH is much higher in the tank than the tapwater is coming out of the tap.

Tap water is around 7.5, the tank runs around 8.5. This is with about 2 bubbles per second CO2 into a cyclone style CO2 reactor inside the tank.

Could the substrate be the cause? I have a mixture of black flourite and a laterite based substrate. Looked like crushed lava rocks though, if that helps.

A couple pieces of mopani driftwood are also in the tank.. could that be helping push the pH up?

I have a couple TLF phosban reactors kicking around somewhere, would it be a good idea to add peat pellets to help bring the pH down? If I do that, how do I know how much CO2 to add to the tank if I aim for a pH target based on the carbonate hardness of the water? (Or would peat bring the KH value down?)

I'll be doing some reading tonight in an effort to wrap my brain around these questions but I'd totally welcome any insights from planted tank gurus .. please and thank you!

[cale262]

What are you using for a co2 reactor (inline/in tank)?
120 bpm in what size of tank?
how much light?
What are you using for filtration ( canister/hob/sump )?


The substrate (fluorite/laterite) won't be the issue and I doubt the dw would affect it much...

I would check all your filter outlets and make sure they are well below the water surface. If you have a lot of surface agitation, lower the outlet even more or fill the tank up more. Are you using a co2 drop checker with 4 dkh water and ph solution to measure the co2 levels?

Ph is also very high for me out of the tap. I use a ph controller to drop my levels down to 7.0 which gives me about 30ppm. I also have lots of circulation throughout the tank (two canisters on my 90). Are you running the co2 on a timer or a ph controller? If you want a ph controller, I can trade you a milwaukee unit for one of those tlf reactors.

Not sure why the ph is higher in your tank. Do you have any limestone in there? That would definetely do it.

[Delphinus]

Thanks for the thoughts guys.. I don't have any limestone though. Yeah I did some more reading and came to the conclusions that neither the substrate or driftwood could explain the high pH. The only thing I can think of is that this tank kind of dropped off my radar for a while and I didn't do waterchanges for a long time (several months) and in the meantime just topped up, so maybe it's been building up for a while.

I kind of kicked my own butt into gear over this over the holidays and have been vaccuuming and waterchanging like crazy so I would have thought by now the pH would be closer to the tap water going in, but maybe I have more to go.

Is filtering through peat a good idea?

I'd take you up on the trade if you like, I don't have a pH controller but I do use a Milwaukee pH meter for checking pH. It's probably due for a probe replacement but I don't think it's shot seeing as I get plausible (and different) readings on other things so I think the >8 pH is probably correct.

So being without a controller, I just set the bubble rate to be reasonably steady and I watch what it does to the pH. When I first started injecting CO2 I found some chart online that matched target pH's to KH readings so I would just find a bubble rate that got me into that ballpark. I'd just increase the bubble rate right now except that I don't see any evidence it's pulling the pH down so I'm not sure what to do.

The tank particulars - 65g, has a sump, bioball tower. The CO2 is from a 20lb cylinder, the regulator and bubble counter are Milwaukee brand, and the reactor is a Red Sea cyclone mixer (this thing) .. I want to eventually upgrade to one of these.

Lights are 4x39w t5's, although I have 2 of them turned off for the moment until I get things straightened out.

I did have a Tunze 6055 for extra circulation in there but I've taken it off for now too in case the agitation was causing the CO2 to gas off out of the water too early. Although it hasn't made much of a difference so that's probably not it. I have a bunch of small tetras though and they seem more comfortable without that extra flow so I might keep it off anyhow. It was there for the loaches in there originally but they don't seem to be minding the lessened flow either.

[cale262]

Originally Posted by Delphinus

...The tank particulars - 65g, has a sump, bioball tower. The CO2 is from a 20lb cylinder, the regulator and bubble counter are Milwaukee brand, and the reactor is a Red Sea cyclone mixer (this thing) .. I want to eventually upgrade to one of these.

....

The sump is your problem IMHO, you're gassing off your CO2...When injecting CO2 you really want to minimized your surface tension/agitation.

If you're looking for that AM 1000, they work excellent, I've run allot of reactors over the years and this one is by far the most effecient IME, I have a few of them, one is BNIB and can be had for half the price if you want it...I bought it for a new system build but then decided to try my hand at saltwater instead of another hitec planted system...

[SeaHorse_Fanatic]

Filtering through peat moss would lower your pH. That's what a lot of discus-keepers do. We don't in the Lower Mainland usually because our pH is low and our water is "soft".

Also, as cale262 stated, reduce your overall surface tension and flow in the tank to allow the CO2 longer time to work in the water column before being dissipated into the atmosphere.

A lot of us locally are using Metricide instead of CO2. Its a concentrated form of the "plant food" Flourish Excel (double the strength) that is used to sterilize stuff in the medical field I believe. There's a local source for Metricide and its about $20 for a gallon which will last a very long time. I manually dose Metricide twice a week and the plants grow like crazy on it.

Anthony

[RuGlu6]

Originally Posted by Delphinus

I should ask this on a FW forum but what the heck let's put some activity in this one ..

I have a planted FW tank, must be coming up on 5 years old, and there's something I've never really been able to understand with this stuff.

I inject CO2 to try to have better plants than algae. For the most part it does not work out. For one, I can't seem to lower the pH of the tank .. at all .. with CO2. In fact, the pH is much higher in the tank than the tapwater is coming out of the tap.

Tap water is around 7.5, the tank runs around 8.5. This is with about 2 bubbles per second CO2 into a cyclone style CO2 reactor inside the tank.

Could the substrate be the cause? I have a mixture of black flourite and a laterite based substrate. Looked like crushed lava rocks though, if that helps.

A couple pieces of mopani driftwood are also in the tank.. could that be helping push the pH up?

I have a couple TLF phosban reactors kicking around somewhere, would it be a good idea to add peat pellets to help bring the pH down? If I do that, how do I know how much CO2 to add to the tank if I aim for a pH target based on the carbonate hardness of the water? (Or would peat bring the KH value down?)

I'll be doing some reading tonight in an effort to wrap my brain around these questions but I'd totally welcome any insights from planted tank gurus .. please and thank you!

I have the same substrate black crashed Haitian moon. PH is always high.
But plants are happy with Co2 injection. what i do is i inject Co2 in to outside canister filter intake. It all get 100% dissolved by the time water comes out of the filter, nothing fancy but works well.
recently changed to low wattage LED and plants love it !
TDS is about 400 ppm
And for algae control shrimps are always the best. I have painted fire shrimps multiplying and some times being eaten but micro algae is under control.