Do you test salinity/gravity of the salt water pond?

[Andy]

So I've read a few of the topics on here regarding the salt water ponds and I'm wondering what the general consensus is regarding replenishment of the salt water.

From what I can tell, topping up salt water with more salt water can lead to a potentially toxic situation as salt water would keep on building up due to it not evaporating.

Topping up with fresh water is not ideal either, as over time, the salinity level would drop. Although the salt does not evaporate, I would think that the hermit crabs would take some with them after bathing.

Does anyone use a hydrometer to test the salinity of their pond? And if so, what type? i.e. I've seen some which are flat and round, and others which are like long cylindrical tubes.

I have a my salt water dish buried somewhat in the substrate, and lined with some aquarium gravel, so I'd rather not take it out daily or more than once a week to remove everything and refill it.

What solutions have people come up with in their own experiences? I may need to redesign my salt water pond to make it more easily maintainable.

[Wai]

To top up my salt water pond, I actually just guess and top it up with salt water, with a small amount of fresh water too. I can't get it to be the exact same salinity, but at least I think this is better than topping up with either fresh or salt water alone. I completely empty the salt water once every one or two weeks (I have an airstone in it).

[appps]

No I just top it up when the level gets low with dechlorinated water and replace totally about every three months with fresh from the sea. I never top up with salt as I think the slightly weaker salt water blend if they do use some up would be far safer than risking over salting the water by topping up with any more salt water (especially as it's only changed totally every few months )

Don't forget that in the wild a lot of their salt water bathing would be done in rock pools where the sun would have evaporated part of the water away or the rain topped up with fresh. They probably only get ideal salt water salinity on the rare occasions they head into the ocean.

[Andy]

OK, thanks, those are helpful answers. I was considering buying a hydrometer, but I think they are designed for aquariums rather than shallow ponds, so probably wouldn't work very well.

[emmac350]

Remember too that as long as there is fresh water available your crabs can dilute the salt in their shell until it's exactly right. I'm sure your crabbies will be fine!