How do you raise your kH?

[Kwyet]

I went down a bit of a rabbit hole today, and would like more info. The main question is what compound to use to increase kH. I started using baking soda about 2 weeks ago to bring my dkH up to 3.

This was because my dkH is 0-1 (I don’t know how to get any more specific than that with a drop test), and I had a rainbow shiner and an hillstream loach die overnight. The parameters didn’t look like a problem to me except that I couldn’t find any consistent info on what the correct kH would be for loaches, so I decided to bring it up a little in case that was the problem. I also figured it would be good for my snails and the shrimp I want to get. There haven’t been any more deaths since then, but I don’t know if that’s coincidence or if that was the problem.

Anyway, the Mini Pellia on the lava rock in my Dutch tank was doing well for several weeks (I’ve been using the turkey baster on it every day), but all of a sudden it has Staghorn exploding out from it. There’s no way I can just remove it manually. I read tonight that it likes bicarbonate, so I wonder if adding the baking soda really encouraged its seemingly overnight growth.

Then I also read that baking soda isn’t a great way to raise kH in a planted tank anyway, because of the sodium. Two other alternatives were mentioned—KHCO3 potassium bicarbonate and K2CO3 potassium carbonate, but I also read that carbonate always becomes bicarbonate in water, so it seems that all of these choices would still encourage Staghorn. It’s not on any other plants or anywhere else in the tank. If I can’t fix this, I’ll have to give up on having the lava rock/mini Pellia in the tank.

I will be cleaning the filter and the tubing, but what is your take on the right way to raise kH just a little bit?

Thanks for reading all of this and any help!

 

[SkaleyAquatics]

I have used K2CO3 in the past and it will raise kH but also raise pH. The issue I found is that pH will spike well above 9 for the first 24-48 after dosing and then come down as it dissolves. This has to be done in a separate storage container because that spike would kill fish extremely quickly like you experienced with the hillstream loach and rainbow shiner.

With that in mind loaches appear to like soft water 18-179 TDS , your water would be fine for them. Can I ask what is your reasoning for wanting to increase kH in the first place? I have always found that stability is more important in keeping fish then trying to be a chemist, and creating the ideal water for them.

 

[Kwyet]

My water change water is prepared in a large Brute trash can the day before maintenance day. I bring the gH to 8, but wasn’t doing anything for kH at the time of the loach and shiner death. Sorry if that wasn’t clear.

I couldn’t find any apparent reason for the deaths, and I recently bought some Japanese trap door snails that haven’t been very active, and I want to get some Neocaridina shrimp, so I started using baking soda to bring the kH of the prepared water up to 3, which will gradually raise it in the tanks. It will also gradually raise the pH, but that slow rise isn’t harmful. Those are the parameters I used for my RO water in Florida for years.

Since I started doing this here (Colorado) for the last two weeks the only observable change has been that the snails are more active and the Staghorn came back on the moss in the Dutch tank. I could just mix a bucket for the Dutch tank as previously without anything to raise kH, and mix 2 more buckets with something to raise kH for the other tanks, but I’m trying to find out if something different than baking soda would be better for this.

 

[Phish Tank]

I have a hillstream loach, my KH is usually 2-3. My TDS in the tank is usually 160-220. I keep a small bag of crushed coral in my filter which can add a little kh when the ph drops below 7, my ph ranges from 7.6 to 6.6.
I've been down the same rabbit hole myself, so I sympathize. One reason I jumped into the rabbit hole was my ramshorn snails shells get eaten away when my ph is under 7.

 

[Kwyet]

I have a hillstream loach, my KH is usually 2-3. My TDS in the tank is usually 160-220. I keep a small bag of crushed coral in my filter which can add a little kh when the ph drops below 7, my ph ranges from 7.6 to 6.6.
I've been down the same rabbit hole myself, so I sympathize. One reason I jumped into the rabbit hole was my ramshorn snails shells get eaten away when my ph is under 7.

Thank you! I read about crushed coral, but I wasn’t sure about using that because I didn’t think you could consistently control the kH level with it. That is, if you add 0 kH water to the tank, it’s going to lower the kH in the tank quickly and then gradually raise it over time with the coral, creating constant fluctuation. Have you had any problem with that?

 

[Phish Tank]

Thank you! I read about crushed coral, but I wasn’t sure about using that because I didn’t think you could consistently control the kH level with it.

It seems to do ok, but I never re-measure the kH right after a water change, I usually wait til the day after. It isn't creeping up over time, which is what i was really worried about. I use about 2 tablespoons.

 

[*Ci*]

My kH out of the tap is zero, as well, and I have always used baking soda to raise kH. In my past goldfish tanks, my ponds and now in my planted tanks (which I raise to 4dkh for my shrimp and snails). I add it the water just prior to filling. I have a few hillstream loaches in one tank.

I have not noticed any problems with using BS - i think that the sodium component is small enough to not hurt the plants and the accumulation is handled with my 50% water change along with all the other compounds that are added. None of my tanks have any staghorn - I have a bit of bba on the wood in one tank, two others are basically algae free.

I don’t have any explanation to offer for your sudden appearance of staghorn or the fish deaths, though. Could it just be about a sudden change in parameters? Did you raise the kH gradually over a few days or all in one dose?

 

[Koan]

It will also gradually raise the pH, but that slow rise isn’t harmful. Those are the parameters I used for my RO water in Florida for years

Just to be clear, the pH itself does not affect your livestock.. it's what the PH change means, for alterations in anything else dissolved in your water at the same time, that causes the problems. IE changing relatively safe NH4+ back into toxic NH3.

Here is a really outstanding - - and in places hilarious - - discussion thread on that very question, way too long to quote here

 

[Unexpected]

Ive used K2CO3 (potassium carbonate). Cheap off Amazon even with lab grade. Rotala Butterfly has dosing info per degree you want to increase per gallons. It does add quite a bit of potassium, so an adjustmen with dosing Is needed. Works well and avoids adding sodium, which to my knowledge is only detrimental to plants and livestock.

 

[Kwyet]

My kH out of the tap is zero, as well, and I have always used baking soda to raise kH. In my past goldfish tanks, my ponds and now in my planted tanks (which I raise to 4dkh for my shrimp and snails). I add it the water just prior to filling. I have a few hillstream loaches in one tank.

I have not noticed any problems with using BS - i think that the sodium component is small enough to not hurt the plants and the accumulation is handled with my 50% water change along with all the other compounds that are added. None of my tanks have any staghorn - I have a bit of bba on the wood in one tank, two others are basically algae free.

I don’t have any explanation to offer for your sudden appearance of staghorn or the fish deaths, though. Could it just be about a sudden change in parameters? Did you raise the kH gradually over a few days or all in one dose?

Thanks! No, I raised the kH in the bucket to 3, that would only raise it by 1.5 in the Dutch tank and 1 in the hillstream tank. Also, the hillstream deaths were before any new additions were made.,

 

[Kwyet]

Just to be clear, the pH itself does not affect your livestock.. it's what the PH change means, for alterations in anything else dissolved in your water at the same time, that causes the problems. IE changing relatively safe NH4+ back into toxic NH3.

Here is a really outstanding - - and in places hilarious - - discussion thread on that very question, way too long to quote here

Yes, I realize that, I just didn’t want to get into a different discussion instead getting my main question answered. Thanks though! I’ll read through the thread anyway later today.

 

[Kwyet]

Ive used K2CO3 (potassium carbonate). Cheap off Amazon even with lab grade. Rotala Butterfly has dosing info per degree you want to increase per gallons. It does add quite a bit of potassium, so an adjustmen with dosing Is needed. Works well and avoids adding sodium, which to my knowledge is only detrimental to plants and livestock.

Thanks, I was wondering about that. So if I use it I just need to adjust the potassium in my macro mix.

 

[Unexpected]

Thanks, I was wondering about that. So if I use it I just need to adjust the potassium in my macro mix.

Correct.

 

[Kwyet]

Thank you everyone! I think I’ll continue the baking soda until my current macro mix runs out and then switch over to potassium carbonate. I also think I’m going to give reverse respiration a try for that lava rock with the moss. I figure it’s so infested that I have nothing to lose by trying it.

 

[Kwyet]

Just to be clear, the pH itself does not affect your livestock.. it's what the PH change means, for alterations in anything else dissolved in your water at the same time, that causes the problems. IE changing relatively safe NH4+ back into toxic NH3.

Here is a really outstanding - - and in places hilarious - - discussion thread on that very question, way too long to quote here

I read the thread. It’s a good one, and I laughed out loud several times.
I didn’t realize that raising kH so quickly with bicarbonate compounds was completely harmless. I thought that needed to be done gradually (not because of pH, but because of the kH itself). I also didn’t realize you could get the degassed pH by boiling the water and straining it. Why then do we always tell people to set a cup of tank water out for 1-2 days? The boiling method would be a lot quicker.

 

[HarryL]

I don’t personally adjust KH levels in my tanks because my tap water comes out to 8 dKH and once added to the tank it adjusts to 5. But I happened to be reading an article Diana Walstad wrote - "Bicarbonate as a Carbon Source" from The Aquatic Gardener Vol.36 No. 2 and I will quote her below to give you some extra ideas.

"In the past, I added baking soda(NaHCO3). However, many aquatic botanists add a mix of NaHCO3 and KHCO3. Sand-Jensen showed that adding pure KHCO3 substantially increased the photosynthesis rate in P. pectinatus compared to adding pure NaHCO3. This makes sense as KHCO3 provides plants with a major nutrient K instead of Na, which is non-essential and can be problematic at high concentrations. THus, I have started adding KHCO3 at a dosage of 1/2 tsp (~3.5 grams) per 10 gal. For my tanks, this increases the KH by about 2-3 degrees."

Based on the idea that plants natively from more alkaline water, where bicarbonates are high and CO2 are low, are capable of using energy to uptake the bicarbonate as their carbon source. I'm guessing that this can be more beneficial over using potassium carbonate if you have a non-CO2 injected tank.

 

[Kwyet]

Thank, that’s interesting! From what I read (not a chemist) potassium carbonate is going to become potassium bicarbonate in the water anyway, and potassium is in both compounds, so wouldn’t potassium carbonate get the same results that she had? I already ordered it, so I hope so, lol!

 

[HarryL]

Thank, that’s interesting! From what I read (not a chemist) potassium carbonate is going to become potassium bicarbonate in the water anyway, and potassium is in both compounds, so wouldn’t potassium carbonate get the same results that she had? I already ordered it, so I hope so, lol!

Yes but the way potassium carbonate becomes bicarbonate is through the reaction with CO2 in the water. So I would assume by having the bicarbonate readily available without using the limited CO2 in the water, it's going to be easier for the plants to utilize both elements however they need. But I'm sure potassium carbonate will work just fine!

 

[Kwyet]

Yes but the way potassium carbonate becomes bicarbonate is through the reaction with CO2 in the water. So I would assume by having the bicarbonate readily available without using the limited CO2 in the water, it's going to be easier for the plants to utilize both elements however they need. But I'm sure potassium carbonate will work just fine!

Oh, I see! That makes sense. Thanks for the explanation. If the potassium carbonate is returnable, I might switch to the bicarbonate. I’ll have to see. Thanks!