help me get a handle on my water chemistry!

Electric Warrior

Apr 29, 2012
Reaction score
Hello all. Now that I have a new tank, I am trying to get a better handle on my water chemistry, since it's something I've generally ignored in my previous tanks unless there's been a problem. So, this is a new 350L tank, external filter already established, moderately planted with mostly slow growers this time. Hardscape consists of large pieces of redmoor wood and about 13 kilo of seiryu stone. Now, I have very soft water, which is great because I keep SA fish, but what I really want to make sure I can avoid is having ph swings, although I am not sure if I've actually ever had one. But my main objective is having healthy fish and plants. With a new setup like this, how often and when should I be checking things like ph, gh and kh? I have a very low kh (2) and even in my older, established tanks this was the same. I did a large wc yesteday, and my readings later that day were ph 6.8-7.0, kh 2, gh 3. My readings today, before lights went on, were ph 6.6-6.8 (its hard to tell exactly, but looked closer to 6.8), kh 2, and gh 4. I've been told in the past to try and raise my kh. so I added some crushed coral to the filter (about a half cup bagged), which seemed to raise it a degree at the time. I was thinking the seiryu stone would bump up the kh, although I have no idea how long it would tae to make an impact. How long after running this tank should I start to see the kh stabilise?

Now to another issue: bba... It's not in my new tank yet, but I have had issues in the past. My first 200L had T8 lighting, 8 hrs a day, and I suffered horribly with bba in that tank. It covered everything eventually - substrate, plants, equipment, wood, everything! It was so bad it got to the point where I wanted to give up quite often. I tried cleaning, spot dosing liquid carbon, blackouts, tinkering with the flow, everything. My second and last tank, a 350L with T5 lighting started out okay, but the dreaded bba came back eventually, although not as bad as in the previous tank. It grew all over my large rock, the driftwood, and a small amount on the equipment. That tank sprung a leak, hence the newly established 350L. I know algae is essentially down to lighting, ferts, and flow/C02. My lighting is LED, on a timer for 8 hrs a day, and I think the flow is okay... I have a Fluval 407 (pump 1450 LPH, circulation 930 LPH) and I also have a powerhead on the other side to move flow towards the inlet and around the back. I dose liquid ferts according to instructions (Profito) and dose liquid carbon daily, although I will admit that previously my liquid carbon dosing was spotty at best with going to work everyday; I was planning on getting an auto dosing pump after furlough ends for me this time. In the past I had a lot of fast growing stem plants and floating plants, although with this tank I am moving more away from stem plants and using more anubias, java ferns, crypts, and buce, although I do have some frogbit, flame moss, tiger lotus and pogostemon helferi currently. I want to try and avoid bba this time around, but I am not sure where to begin? I don't want to go high tech and start running pressurised C02, so what should be I looking for to keep my pants healthy and keep that horrid bba away?

Thoughts? About any of this?
Last edited:


Fish Fanatic
Jan 26, 2021
Reaction score
Nanaimo, BC
Just curious about the pH in your existing tank and the amount of Seiryu stone you used in it. Your input pH values seem very close to what my current water supply is like. In my larger tanks they stabilize to 6.4 pH which is pretty much where I like it. I only have inert rocks, natural wood and Tropica aquarium soil in them, water changes once every 2 weeks. In those tanks the gH is 2 degrees and the kH is zero, or as best I can tell. In those tanks I only get green dust algae that grows quick but it is easy to remove, I keep the lighting pretty high with the one tank and it is just at the verge of an algae bloom to encourage the plants. I haven't seen or had any bba in those tanks. Nitrates in all tanks kept <= 20 ppm.

I am now also experimenting with nano tanks. One 10 gallon has been a challenge with pH, using the same materials I use in the larger tanks I was getting pH values below 6.0 which is the lowest I can currently measure to. That was too low so I placed a single fist size cobble of fairly pure limestone (nearly marble) into the tank to raise the pH. Over a month of time the pH in this tank has risen to 6.5. In this tank I have seen the first occurrence of what might be bba in any of my tanks since moving. I think I may have to change the water change cycle for this tank if I want it to stay at 6.4.

Past experience in my previous house I had water that was from a well with high kH and pH. So I maintained a tank with limestone and shells for Mbunas. The pH of that tank was 7.8 sometime nearly 8. That tank had a constant issue with BBa, but I wasn't as technical a fish keeper as I am now, so I couldn't say if the bba was because of some other factor.

In one of my larger tanks I am experimenting with SeaChem Flourish Excel. I have mixed feelings about it. It has clearly helped with algae and with the various Echinodorus plants I have, but has clearly set back my Sags, Java Fern, and Vals (I struggle with the sags because I have a tank that is 25" tall). I am only half dosing but I have been half dosing by full dose every second day. Recent research on this is that if I do use this, or other liquid carbon solutions, I really should be dosing daily, but with less. I will probably not continue with it because I am not that regimented.

Overall if I would summarize my experiences it would be:
1) BBA seems prefers more alkaline water
2) Rocks can be used to change the pH but how fast and what the end point ends up being is highly dependent on when the water changes occur. The change is more gradual than crushed shell.
3) The more you try to force a pH point from the point the pH would at be if you did nothing, the more consistent and frequent your water changes will have to be otherwise you will experience more issues with pH swing.
4) The jury is still out for me on the liquid carbon yea or nay.


Most reactions - Past 7 days