Seeking advice- HC in low tech?

[Fern]

You could blanch kale, spinach would go mushy tho, so probably better just washed, as is the parsley, and then you can put onto a veggie clip.
Fern

 

[sciencefiction]

Yes, raw is fine.

 

[tim]

Back to your original post sacha, hc will stay alive rather than grow without a carbon source ime liquid carbon would do though, if you need a filter I may have an old Azoo hob knocking about you could have.

 

[Sacha]

Thanks a lot for that Tim.

I appreciate all the advice in this thread, some really knowledgeable and patient members here.

 

[dw1305]

Hi all,

I know it sounds silly, but my number one priority is getting this snail healthy, it's not nice seeing his shell cracking up

Put him in your tap water, unfortunately the snail can only secret shell at the edge of the mantle, so it won't repair the cracks.

So are you saying that if I add some non- oxidised calcium, this will compensate for the acidic water, and the carbonic acid from Co2?I thought that no matter how much calcium is in the water, if it is acidic, the shells will always erode?

You are right acidic water will always erode snail shells.

I only want to add calcium. I don't want to add any carbonate or other minerals. I don't want harder water, just more calcium

Snail shells are made of biogenic calcium carbonate (CaCO3), and you can't really add one without the other successfully, you need calcium (Ca++) ("dGH") and carbonates ("dKH" in solution as bi-carbonate HCO3-).

Problems with shell erosion are to do with both pH and the CO2 ~ HCO3- equilibrium. If you add enough CO2 to reduce the pH below pH7 shell erosion will occur, and even though that CaCO3 will go back into solution as CO2 levels fall, it will precipitate out as "scale", so there will be a net loss of shell, although the amount of CaCO3 remains constant.

If a snail (like your Nerite) naturally comes from hard water it won't be able to build its shell when the pH is below pH7 or Ca++ or HCO3- are in short supply, it doesn't "need" to have these adaptations. A mollusc like a Pearl Mussel, that can build shell in acid water, will grow much more slowly, and have biologically costly adaptations to allow it to concentrate Ca++ ions in its shell secreting mantle cells.

If your pH goes below pH7 you won't be able to keep a lot of molluscs. Burrowing gastropods like MTS are much more likely to survive lower pH levels as sediments will often be oxygen depleted (reducing or negative REDOX) and acidic. Even then if you look at MTS from softer water the older shell whorls will be eroded and make actually be missing, despite being initially laid down in a really thick layer.

but how they extract it from the water is not something I am certain of

It doesn't matter how you supply the calcium ions, that are transported to the mantle to build new shell, they can be absorbed directly from the water, via gills or epithelium, or from food in the the gut.

The only thing I'd add personally is that a GH test tests for total calcium and magnesium levels including oxidized ones that are no longer useful to inhabitants and plants, etc.. which eventually happens if not replaced. ......... to a GH reading of any amount does not indicate absolutely anything useful.

I think this isn't quite right, in an oxidising environment the calcium will be bound as CaCO3, but Ca++(and HCO3-) ions will be going in and out of solution all the time due to the common ion effect and the CO2 ~ HCO3- equilibrium. If you look at the REDOX values for sea water (or the surf zone of Lake Tanganyika) you will get values in the 300-450 mV range, and under these strongly oxidising environments the Neothauma shell beds, or coral reefs, can form, and aren't eroded, lasting for millennia.

Eroding snail shells on another hand indicate the water is lacking non-oxidized calcium and is too high in oxidizers that extract the only available free electrons around left which happen to be from the calcium in the poor snail shells.

This isn't going to happen in water with high dGH/dKH, because the reserve of carbonate buffering is always going to supply Ca++ and HCO3- ions. In a marine tank you might need to add calcium continually as the coralline algae, corals and molluscs deplete the Ca++ ions from the water, but in a fresh water tank you've only got molluscs and food and water changes (with water with some dKH/dGH) should be sufficient to replenish mineral levels.

cheers Darrel

 

[sciencefiction]

I think this isn't quite right, in an oxidising environment the calcium will be bound as CaCO3, but Ca++(and HCO3-) ions will be going in and out of solution all the time due to the common ion effect and the CO2 ~ HCO3- equilibrium.

This isn't going to happen in water with high dGH/dKH, because the reserve of carbonate buffering is always going to supply Ca++ and HCO3- ions. In a marine tank you might need to add calcium continually as the coralline algae, corals and molluscs deplete the Ca++ ions from the water, but in a fresh water tank you've only got molluscs and food and water changes (with water with some dKH/dGH) should be sufficient to replenish mineral levels.

Happened to me Darrel, not long ago. Gh 14, Kh 5, eroded snail shells. I did a lot of reading then and it's very much possible. It's to do with the Redox balance. When Ca2+ Mg2+(Ca->Ca2+ 2e-) have lost their positive electrons they apparently are still detected on a Gh test.

 

[dw1305]

Hi all,

Gh 14, Kh 5, eroded snail shells. I did a lot of reading then and it's very much possible. It's to do with the Redox balance. When Ca2+ and Mg2+ give away their positive electrons they apparently are still detected on a Gh test.

Interesting, it might explain why in some of my tanks I can keep Red Ramshorns in (but they always have eroded, paper thin, shells and never get very large) and some I can't, even though the water changes etc. are similar (I only measure conductivity and pH occasionally, so I don't know what the dGH, dKH (or pH most of the time) are.)

Was that without water changes? or with added CO2?

cheers Darrel

 

[sciencefiction]

Hi all, Interesting, it might explain why in some of my tanks I can keep Red Ramshorns in (but they always have eroded, paper thin, shells and never get very large) and some I can't, even though the water changes etc. are similar (I only measure conductivity and pH occasionally, so I don't know what the dGH, dKH (or pH most of the time) are.)

Was that without water changes? or with added CO2?

cheers Darrel

No CO2, water changes used to be always 50% weekly, neglected it for a good while like 3-4 months only topping up and then saw the eroded snail shells on many snails. My other tank with way lower Gh7, Kh 2 had perfectly happy snails at the same time which left me puzzling why on a tank with Gh 14, Kh 5 and Ph 7.4 I am having snail problems.
My tap water is hard (Gh12, Kh 8), so I started back to back 50% water changes and added dead coral pieces and snails looked perfectly fine 2-3 weeks after.[DOUBLEPOST=1402322775][/DOUBLEPOST]If this can happen with originally hard water then imagine what can happen in tanks initially filled with water not containing many reducing minerals at all. But it's not the value of Gh that the test showed that matters in both tanks which is the strange part otherwise on my little tank with no water changes for a year and lowish Gh and Kh my big ramshorns should have died. It's something more complicated than a Gh reading or water change schedule and I don't even think it was because of lack of water changes but some other chemical reactions that were different from my other tank. The only thing that explains it is bad Redox.