koffee

I just aerated some water... actually ran some through my stand mixer with a whisk for a while since I don't have a spare air pump. I have a SW alkalinity "fasTest" kit from Aquarium Systems. That has instructions for testing FW, along with a formula to convert to German KH. I also have FW Master Test Kit from Aquarium Pharmaceuticals which includes two pH tests: 6.0 to 7.6 and 7.4 to 8.8.

So far, every time I've tested KH (tank water, tap water, aerated), I get results around 9.1 to 9.8.

Tap pH seems to be aound 7.6, which made no sense because of the high KH. But this water I just aerated for only 15-20 minutes reads around 8.2 pH. That brings the CO2 calculation into a more logical range, I think. Maybe I should start thinking about African Cichlids with such a high pH.

I've been (so far) able to keep my tank at 6.8 to 7.0 pH if I really keep an eye on my DIY CO2 bottles. This is a 29g tank.

I currently have 4x20W CF. Only two are 6500K, and the others are average house bulbs. I was planning on replacing these soon, hopefully with 4x25W 6500K CFs, or at least swap the two house bulbs for 6500K. I run two bottles so I can alternate swaps, and they run through a bubble counter to a powerhead. No fancy reactor... just the venturi. The tank was recently rebuilt to add sand so the plants haven't had much time to really show any major effect. Plants are: Crypt wendtii, some broad-leaf sword, a common Val, 2 Anubias barteri (nana and coffeefolia), some Java Fern, some Ludwigia Repens, and some Sags (dwarf and other).

Before anyone responds, yes, I know I should do pressurized. But I cannot afford the equipment yet. If it becomes too hard to maintain a stable pH, I will drop CO2 first. But let's ignore the difficulties with DIY and assume my pH is stable. I also cannot upgrade the lights beyond the CFs for now.

Now the questions:

Is my light too low or too wrong for CO2, even if I upgrade to 4x25W CF? Should I try to throw in another bulb or two? (That's more affordable right now than advanced lights or pressurized CO2.)

Do all my readings seem logical? At first, the tap pH and KH confused me. But if aeration raises the pH, I guess that means my tap if full of CO2. However, this also means that I am putting well over 40ppm into my tank water with a supposedly ineffiecient delivery mechanism. Why would I invest in a diffuser and silicone tubing if my powerhead and standard tubing is that effective?

I do have obvious algae on the light colored rocks and anubias leaves. None of it is bad (hair, etc) algae, and I want to see some algae. If I get rid of CO2, should I lower the wattage? Should I also cut back from 12 hours?

Note: the tank is about 5-6 feet from the nearest window and gets some sun in the afternoon/evening. (Window is northern exposure.) There is still well over 12 hours of daylight coming in that window. (Sunrise was about 6:30 am, and sunset is about 9:30 pm today.) There is also room lighting on and off, but most of that is a basic 60W incandescent in a ceiling fixture.

trystianity

Why does this make no sense? By my calcs you have at most ~ 7 ppm CO2 coming out of the tap @ KH 9.8. My tap water comes out at about 15 ppm CO2, others have more, 7 is really not that much at all. There is really no need to aerate your water before you do water changes in a planted tank unless you are trying to severely limit CO2, for example in a non CO2 injected tank.

I don't see any problem with your current lighting, you should be fine with what you have now. Upgrading light is up to you. Normal household CF bulbs will grow plants just fine in my experience, the only problem is that the colour of the light isn't all that attractive, a matter of personal preference really.

I'm not sure how you got over 40 ppm, by my calcs you're getting about 37 ppm CO2 maximum if your pH is 6.9 and KH is 9.8. Nothing wrong with that as long as your fish don't mind it. Just be wary of when you're testing it, you will get more CO2 showing up when you first replace your yeast bottles and the supply will slowly taper off as the mix ferments. If you're using yeast on a tank that size I would run multiple bottles and replace them frequently to maintain the desired level of CO2. It can work if you're willing to look after it, in the long run a pressurized setup will be less maintenance and also less money. If you're saving up for anything, save up for a pressurized system.

Why would you get rid of CO2? If you did want to go with a lower light non CO2 setup (there are benefits - lower maintenance and much slower growth) then yes, I would decrease lighting to under about 60W CF on a tank that size. Otherwise, I would just leave it as is. If it's working for you then why change it? 12 hour photoperiod is fine as long as you're consistent with it for both CO2 and non CO2 tanks.

The only thing I would suggest is to add some more plants. Mostly faster growing stem plants that will give you more wiggle room as far as nutrition goes and outcompete any potential algae. Also you didn't mention anything about fertilization routine. Sounds like your lighting and CO2 is fine to me but that isn't all you need to grow plants.

koffee

Actually, I did the calculations yesterday, and I was reading a lower pH and higher KH. Now that I think I have more accurate readings, the tap isn't as mysterious.

I don't. I aerated water so I could test it as a reference.

Again, I was mixing a prior test with this one. But still, if it is really pH 6.8, that is over 40ppm. I run two bottles currently, and stagger the swaps. My fish are not gasping, and my RT Shark is deep black and bright red... I trust his judgement more than mine. I've tested early in the am when I say 6.8 (maybe even 6.7), and that should be when the CO2 is highest.
Still, though, even if I'm in the 30s... can my standard aquarium tubing and powerhead be that efficient?

I am more than willing, but can't afford the equip yet. I don't see how it saves money, though. You still have to pay to refill the tanks of CO2.

Reason 1: because I am doing a real bad job of it. This post was to ask for advice so I could find out if I am or not.
Reason 2: my pH starts fluctuating wildly because I can't maintain a steady CO2 output. That is also the reason to go pressurized, but when combined with no $, removal seems like the only choice.

Oops. Substrate is mix of gravel and flourite with sand on top. It ranges from 2.5 to 5" deep. I am using plant tabs near the crypt and sword - not the number suggested for the tank size, but I also use Kent Freshwater Plant and Kent Pro-Plant according to directions. Should I do more?

I'll try to add some more stem plants. I had Anacharis which thrived but I don't like the look, and recently replaced it with Ludwigia. Most commonly (at the LFS), I have Anacharis, Moneywart(?), Ludwigia, and Hornwart to pick from. There was some barcoba(?) too.

Btw, I can see a stream of tiny bubbles rising from under my anubia v. nana. So I guess something is working.

Thanks for the advice!