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I'm considering the calcareous substrate route, like Caribsea, which should release enough mineflakes to maintain my water hardness. However, I'm thinking there might be some fluctuations with each water change - would that be a problem? I was wondering if using bicarbonate of soda could help buffer the water and prevent pH and hardness swings after each change?

glitcher wrote: ↑Thu Sep 18, 2025 7:05 am I'm setting up a new tank, thinking of making it an all-male peacock tank, and I'm considering altering my water parameters. Normally, I avoid messing with them, but I'm thinking of making an exception this time. My water's soft - 1-2dH KH and 4-5dH GH - so I want to raise the hardness. Has anyone got any advice on the safest, most consistent ways to do this? I've come across Epsom salts and bicarbonate of soda a few times, would be great to know how well they work.

Hi, I've been doing some research and I found that using a calcareous substrate like CaribSea sand seems to be the way to go for raising the hardness in my tank. It's a permanent change and it'll release the necessary mineflakes to keep the water hard. However, I'm still a bit concerned about the fluctuations in pH and hardness during water changes. I was thinking of using bicarbonate of soda to buffer the water and prevent these fluctuations. Has anyone else used this method?

Bicarbonate of soda, or baking soda for those who prefer the common term, is limited in its application when it comes to water hardness. It contains sodium and carbonate, which means its primary function is to increase KH, not GH. GH, as we've discussed, is comprised of calcium and magnesium, so adding bicarbonate of soda won't have any effect on it.

glitcher wrote: ↑Thu Sep 18, 2025 7:05 am I'm setting up a new tank, thinking of making it an all-male peacock tank, and I'm considering altering my water parameters. Normally, I avoid messing with them, but I'm thinking of making an exception this time. My water's soft - 1-2dH KH and 4-5dH GH - so I want to raise the hardness. Has anyone got any advice on the safest, most consistent ways to do this? I've come across Epsom salts and bicarbonate of soda a few times, would be great to know how well they work.

Bicarbonate of soda isn't the answer here, it's only a temporary fix and not suitable for long-term use. I recall reading an article by Dr. Stan Weitzman on soft water fish, and he mentioned that bicarbonate shouldn't be used long-term as a buffering agent.

Regarding the fluctuations, I think it's a case of trial and error. Once a tank's biological system is established, it tends to remain stable. You might need to adjust your water change schedule, opting for smaller volume changes to minimize the impact. I haven't dealt with this issue in a while, my experience dates back to the 1980s, so I'm sure others on the forum have more recent insights to share.

Thanks for all the advice guys. I'll probably start by trying out the calcareous sand and see how well it works for me. If it does the job, I won't need to mess around with any other additives.

Appreciate the suggestion, just had a look at SaltyShrimp, seems like a solid option for water conditioners and mineflakes, might be worth considering alongside the other recommendations.