pH problem in tank

[NorthCoast]

Good question. And my I don't want to overstate my understanding of science.

Thanks for the explanation. This is a confusing subject and as will all think aquaria there is a lot of conflicting information out there. I suppose given that we all have different parameters, goals, stocking, substrate etc. this can be expected.

You almost need as much faith in this hobby as you do knowledge. At some point, unless you have a deep understanding of the science (which I certainly do not) you kind of have to believe someone. It seems both Dennis Wong and Tom Barr are of the belief that KH is misunderstood and while it has an important role, for the most part you can run it as low as possible, at least provide your substrate has a buffering capacity.

Again, I’m just in the beginning stages of wrapping my head around this, but here is Tom Barr discussing the actual quantity of kh required to provide buffering.

The mystery of KH and running with zero KH

It's been a while but more and more aquarists seem to be running their tanks at zero KH. These tanks are very healthy and beautiful so it seems to at least not hurt the plants and it may be very helpful, especially with some difficult species. As you may know, KH is the presence of carbonate and...

scapecrunch.com

In a separate discussion, he had referenced the ideal kh as being as low as possible for the planted tank.

Dennis Wong (2hr aquarist) is another advocate for leaving kh low and living with co2 related ph changes.
Discussed around 18 minutes

Anyways, apologies for my shallow understanding of the topic. I appreciate the knowledge here on this forum and it is invaluable to new aquarists.
In my situation, given that I have a kh of essentially 0 from tap, and my substrate will absorb any kh added, then I will have to live and learn with a kh of 0. So far so good but I’m sure there are challenges ahead

 

[Connswater]

It is certainly complicated. I went on the JBL site they have some excellent tables but definitely err on the side of caution and make the distinction between planted tanks without fish and planted tanks with fish. They suggest a KH floor of 4, so don't think that is helpful to you and they are fairly conservative on CO2 levels with fish. Link: Keeping an eye on the most important water values

I'll watch your links tomorrow, off for dinner out now. Kind regards.

 

[dw1305]

Hi all,

Hi all, I think JBL's table which I have lifted from their website ....

<"Call me cynical">, but I think their advice has much more to do with trying to <"sell you product"> than anything else.

<"JBL Aquadur"> - <"so all right">, other than the sodium bicarbonate (NaHCO3) and all that <"for a mere"> £83 / kg ...........

I honestly think that supplying the essential nutrients for plant growth is the thing that matters and everything else is froth.

.... I think it is particularly suitable for people who want plants, but don't want excessive growth or to use EI etc. I think plants are the gift that keeps giving, in water quality terms, so if you keep sensitive fish it makes sense as an approach.

<"Fish are slightly different">, and I would base water parameters (and plants) on their requirements.

Cheers Darrel

 

[Andy Pierce]

It isn't exactly that they are wrong, it is just that <"the past is a different country">. Personally I think advising people that to have some dKH isn't a bad idea, I'm guessing that it is only really keepers of blackwater fish and dedicated aquascapers who are going to keep their tanks at very low dKH levels.

Also keepers of caridina (not neocaridina) shrimp are going to want a very low KH.

It is certainly complicated. I went on the JBL site they have some excellent tables but definitely err on the side of caution and make the distinction between planted tanks without fish and planted tanks with fish. They suggest a KH floor of 4, so don't think that is helpful to you and they are fairly conservative on CO2 levels with fish. Link: Keeping an eye on the most important water values

KH of 4+ is fine for neocaridina but caridina shrimp are going to be pretty unhappy. It might just be my mistaken impression, but I don't see a lot of people trying both plants and caridina shrimp with roughly equal emphasis. There are lots of examples of very shrimp-focused (i.e. breeding) caridina tanks but not much about aquascaping including caridina shrimp. Anyone else giving this a go?

 

[Connswater]

Dennis Wong and Tom Barr are of the belief that KH is misunderstood

Thanks for the links, read and watched them. Appreciated. And I don't claim to understand the chemistry of KH/acid fixation capacity, I have to rely on others and I need to take care with measurement standards I sometimes get mixed up between dKH and ppm

Directly relevantly to KH. it seems the science (T Barr) says that the cut off point is very low for KH to act as a buffer, for plant health with CO2 injection. Tom Barr is someone who should know.

I did believe/assume and read that buffering was reliant on much more KH than it seems is the case. I have always believed 2 dKH was the absolute floor for peace of mind.

I can only now guess, that a tank with a very low KH with plant melt from acidification, that this is, in reality, because of perhaps other more complex to unpick effects of say - I'm guessing here - substrate and filter. Certainly tanks can become more acid over time via decomposition. Association is not of course, cause and effect, and unpicking things without proper scientific experiments is never easy.

However, (there is always a however!) for those like me who keep a cosmopolitan range of fish in planted tanks, it is hard to know if very low KH tanks are appropriate, but that is not it seems related to the appropriate use of CO2 injection. Given my tap water is often >14 dKH, I remain unlikely to take tank water mixed with rain water to <8 so I wouldn't be putting to the test the issue of very low KH and livestock.

I honestly don't really know how living with the very low KH water you have will impact upon fish health. I guess most characins should be fine. According to Allagayer & Teton black water in Peru can be very low, they report KH as lower than 2 ppm. But, that was the only very low KH environment they measured. Asia, Malayan river was higher in fact much higher.

Thanks again, there were a number of other matters which challenged some of my working beliefs in the hobby, but we will leave those to another thread.

 

[dw1305]

Hi all,

Certainly tanks can become more acid over time via decomposition. Association is not of course, cause and effect, and unpicking things without proper scientific experiments is never easy.

I think that was partially why Diana Walstad liked to start with a lot of carbonate hardness in her substrate. Originally she didn't advocate any water changes <"Walstad revises">, so she needed a reserve of dKH to counter <"old-tank syndrome">.

Given my tap water is often >14 dKH, I remain unlikely to take tank water mixed with rain water to <8 so I wouldn't be putting to the test the issue of very low KH and livestock.

I have the same "issue", even our <"rainwater has some carbonate buffering">. I just don't try and keep black water fish.

I'm a snail fan, so I like the water to be <"hard and alkaline enough"> for Tadpole (Physella acuta), Red Ramshorn (Planorbella duryi) and Malaysian Trumpet (Melanoides tuberculata) snails

cheers Darrel