Crushed coral vs. baking soda

[carfey]

I usually add a little baking soda to my water every water change to keep the buffer up especially since I inject CO2 into my tank. I was just wondering people's opinions on this practice.

As far as I can figure, adding baking soda every change in the amount you determine necessary is more stable than filtering through crushed coral. If you do that, you can keep your KH relatively consistent from before a water change and after. If I were to filter through aragonite or crushed coral, would the KH not drop a lot when I do a water change with my very soft water? Wouldn't it just climb and climb until I change the water again thus lowering the KH. That would cause the pH to fluctuate wildly right? I may be wrong, but I'd like to hear what everyone thinks!

Adding baking soda may sound like a nuisance but it really isn't and at the current time, it seems to me that it's a better idea. If there are some factors that I'm missing or if I'm completely off-base, just let me know!

PS: My 55 gallon planted tank currently has 4 three spot gouramis, 11 glowlight tetras, 2 SAEs, 2 panda corys and 4 otos. What should I add to the tank? I need at least one if not two more female gouramis to spread out the aggression. If I were to do that, which should I add more of? I think I might like a couple more corys so they're more comfortable in their environment. I'm not really looking for more species at the moment. Thanks for any help!

 

[wetmanNY]

Compare the solubility of sodium bicarbonate and calcium carbonate (the "aragonite" of coral and shells). One dissolves all at once, exerting all its action at a go. The other dissolves slowly, eroded by the CO2 as carbonic acid.

 

[carpguy]

I'm in the same boat as far as overly soft water and CO2, and I decided to use crushed coral for the same reason -- it seemed to me to be more stable.

You make a good point about the KH being diluted at water changes, but it seemed to me that with the baking soda the buffer would be slowly be depleted between changes and then jump up at the water change. With the coral in the filter it stays steady during the week, although it may take a slight dip during my small regular water changes. If I did a very large change I might doctor it, but I only change about 1/6 every 5 to 7 days.

I have too much trouble with the test kits to be able to be 100% about my numbers, but they seem to be steady. I think there will always be small sways (day to night), and that as long as its stable within a certain range its probably ok.

 

[carfey]

Thanks guys! You make good points. I guess what I'll do is try out crushed coral and see how it works for myself!

 

[JSchmidt]

Originally posted by carpguy
I'm in the same boat as far as overly soft water and CO2, and I decided to use crushed coral for the same reason -- it seemed to me to be more stable.

You make a good point about the KH being diluted at water changes, but it seemed to me that with the baking soda the buffer would be slowly be depleted between changes and then jump up at the water change. With the coral in the filter it stays steady during the week, although it may take a slight dip during my small regular water changes. If I did a very large change I might doctor it, but I only change about 1/6 every 5 to 7 days.

I have too much trouble with the test kits to be able to be 100% about my numbers, but they seem to be steady. I think there will always be small sways (day to night), and that as long as its stable within a certain range its probably ok.

I use crushed coral for precisely those reasons. Well stated!

Jim