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Discussion Starter · #1 ·
Hey folks,

Just bought a 40 breeder to re-enter the hobby after ~10 years. Going without CO2 and not looking to do anything too challenging. I want to get to a pH of 6.8 or a bit below for my ideal fish (Apistogramma borellii, maybe cherry barbs and corydoras), but after taking my tap water and aerating it two days (comes out the tap at 8+), the lowest the pH will get is ~7.6.

I'm planning to have some driftwood, but it's wood that's been in aquariums already for years, so I'm not sure how many tannins it will leach to lower pH. Besides, if it starts to look like blackwater, I'll pull them out with carbon for a day- the wife doesn't like that 'dirty water' look.

Options for lowering pH seem pretty limited- my KH is 3 and the GH is only 2. Peat would lower the KH as well, right? As for acid and base buffers, I think that will just mean long term instability as I fail to keep it exact with each water change. Any ideas?

Cheers!
 

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Well, your options are to 1) add CO2 (which you don’t wish to do), 2) add an acid, 3) use RO or distilled water, or 4) use substrates designed to achieve various pH levels. The nitrification process also consumes KH, slowly acidifying the water. My guess is that you won’t want to cut it with pure water, which leaves acids.

You can use strong acids, such as Hydrochloric acid (HCL), Sulfuric acid (H2SO4), Nitric acid (HNO3) or Hydroiodic acid (HI), which will quickly do the job, but with some risk if you don’t handle them correctly, or you can use weak acids, such as ascorbic acid, Fulvic acid (humic substance) and other sources of tannins (humic substances) such as driftwood, peat and various leaves (catappa, almond, oak). The weak acids will take longer. I’ve found that using Fulvic acid (available as a powder) allows better control since you are dosing it. This also allows you to control the amount of discoloration to your taste, but the discoloration is quite mild.
 

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Check your municipal water report. Some put soda ash in to raise ph.

Other than that higher pH right out of tap is normal. And 7.6 after sitting out is only just a tad high for kh 3 but there may be a resolution issue with the tests??

I have a 40 breeder too and it uses Fluval Stratum for substrate. It kept pH right around 7.0 with 4kh tap water (8+ right out of tap, 7.8 a few hours later, 7.5 after a day or 2). I have since switched to RO on that tank but I have another 20gallon next to it with newer Contra Soil that gets tap water changes, same 4kh, and it's at about 1 kh, 6.9 pH give or take a tenth.

Those active substrates are pretty good at keeping an even keel but they do give out anywhere from 6 months to a year or so. I'm sure there are people that have gone longer or shorter. :)


Edit Ha! @Deanna beat me to it :)

Sent from my Pixel 3 XL using Tapatalk
 

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Hey folks,

Just bought a 40 breeder to re-enter the hobby after ~10 years. Going without CO2 and not looking to do anything too challenging. I want to get to a pH of 6.8 or a bit below for my ideal fish (Apistogramma borellii, maybe cherry barbs and corydoras), but after taking my tap water and aerating it two days (comes out the tap at 8+), the lowest the pH will get is ~7.6.

I'm planning to have some driftwood, but it's wood that's been in aquariums already for years, so I'm not sure how many tannins it will leach to lower pH. Besides, if it starts to look like blackwater, I'll pull them out with carbon for a day- the wife doesn't like that 'dirty water' look.

Options for lowering pH seem pretty limited- my KH is 3 and the GH is only 2. Peat would lower the KH as well, right? As for acid and base buffers, I think that will just mean long term instability as I fail to keep it exact with each water change. Any ideas?

Cheers!
I have similar water. What I did in a 50g was to keep lite CO2 flow 24/7 to go pH8 -> 7. Without any surface agitation a paintball tank would last 3 months. Dont need much CO2 if there isn't any surface agitation. Probably a good idea to run an airstone at night, depending on how high your lights are.

Its really the easiest /foolprrof method. If you aren't dropping more than about 1 ph, then you only need like 1-2bps. Set and forget. Cheaper and easier than RO.

In fact, you probably dont even need a reactor or diffuser. Just put an upside down jar, feed the CO2 in morning, and it will disperse through the day.
 

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Discussion Starter · #5 ·
Hey Everyone,

Thanks for your replies- I'm still going to stick to no CO2 for the time being- I have a hang on back filter.

I guess I'll look into weak acids or consider a substrate for the pH. I'll pick up some calcium chloride and magnesium and try dosing that with every water change to replace what substrate or decomposition of wood is likely to pull out.
 
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