[grandweapon]

A couple of months ago, I added 10 Malaysian Trumpet Snails into my 65gal community tank. I frequently leave leftover food in the tank to allow some of my shyer fish (corys and ancistrus) more time to feed. 2 months after first introducing the MTS, I have a MTS population explosion of epic proportions. I have literally thousands of MTS now.

I have been manually removing snails every night, and added a dozen Assassin Snails who are doing a decent job controlling the MTS population, but it's going to take awhile before the MTS population reaches a manageable level.

While the MTS are not doing any real harm other than being unsightly, I have noticed a pronounced increase in the pH level of the water. My tap water is roughly pH 6.8. My ADA Amazonia substrate and 2 large pieces of driftwood brings the pH down further to 6.6 (last tested pH around 3 months ago). I tested my pH today (with API Freshwater Master Kit) before a water change and pH looks to be 7.0 or even slightly higher than that.

I am assuming the dead MTS shells are causing the pH to rise. Have anyone encountered something similar? Should I start adding some peat moss or almond leaves to lower or at least stabilise the pH? I have GBRs and they don't really appreciate too high a pH.

 

[Diana]

No, dead snails do not raise pH significantly. The composting of their body lowers the pH, and the shell could raise the pH. Net is no significant change.

What may be happening is that the Aquasoil has removed all the carbonates it is capable of holding, so the carbonates are staying in the water, and this is keeping the pH up a bit.

pH is not a stand alone value. It is controlled by many of the minerals and salts in the tank, which can act as buffers, stabilizing the pH at a particular level. In aquariums one of the biggest buffers is carbonates. High carbonates usually means high pH that is difficult to change. Low carbonates generally means something else is going to control the pH. pH may be low from several acidic reactions going on- CO2, decomposing things, peat or driftwood, leaves (including oak, Indian Almond, other).

Several of the Aquasoil substrates, and some others (such as montmorillonite clays) can remove quite a bit of the carbonates from the water. This allows the pH to drop. (In some of my tanks it took laboratory grade tests to show the pH was pretty close to 5). These substrates can only hold a certain amount of carbonates. When they get full, they no longer remove carbonates from the water.
The carbonates remain in the water, and this controls the pH, and it rises.

More important than pH is the GH of the water.
Soft water fish evolved in water with very low mineral levels. Test the GH and keep it in the preferred range for your most particular fish.
Then adjust the KH so that the pH is in the right range.
When I was breeding Rams I used a blend of reverse osmosis and tap water to create GH and KH of about 2 German degrees of hardness, then filtered the water through peat moss overnight to drop the pH and add tannins that black water fish need. End result was pH in the low to mid 6s, and baby Rams.

 

[AWolf]

I have some glass bottom tanks with nothing but fish and plants, and the pH rises after water changes too. I go from a 5.8 pH from the well, to about 6.8 by the end of the week. Plants and ferts can change pH. I believe plants can do it by adding a carbonic hardness through photosynthesis, using carbon from CO2 or Atmosphere. Ferts and fish through minerals (calcium/magnesium) and food/detritus breakdown (more carbon).