Is reptoguard a reasonable substitute for wondershell?

[ChefConfit]

All but one of my local store except one don't carry wondershell, and the one that does carry it is always out of stock. Every single store always has reptoguard though. As far I can tell they are very very similar in both function and ingredients. 

[Daniel]

Isn't reptoguard some sort of medication?

[KBOzzie59]

It contains "slow-release, medicated sulfa".  I'd say not a direct replacement.  If you are in the US why not just order from the Coop?

https://www.aquariumcoop.com/products/wonder-shell

[ChefConfit]

So I did some more research. 

@Daniel some of the wording on the package suggests it's a medication but it's 99% Calcium Sulfate. It's meant as a slow release calcium additive to turtle tanks to protect their shells. 

So if your trying to increase Calcium Reptoguard should work but it lacks the additional minerals and water conditioner found in wondershell. It also doesn't increase Kh just Gh. 

@KBOzzie59 for the same reason that I don't buy all my other inexpensive consumables for my tanks from the coop. If I'm placing an order and know I'll need it soon I'll gladly add it on, but I can't justify paying $5 shipping on a $4 purchase if there's a reasonable substitute available locally.