Are these ornaments safe? (pics included)

[grimms]

My grandmother gave me these pieces to put in my tank, but just wondering if they'll be safe for a new planted tank I'll be setting up.

The first one has these red spots on it, and won't scrub off. Do you think it's fine?

The second one looks like it has paint and some dirt. Will the paint affect my tank in a bad way? 

Is there a way to properly disinfect both of these for the tank if I can use them?

p.s I did not get these rocks/shells myself, my grandmother got them a LONG time ago. 

Thanks.

[Gator]

@grimms; If you want to set up a blackwater tank, these rocks are not good for blackwater tanks and may even damage your plants. These rocks look like long-dead coral which are made up of Limestone and would increase your pH beyond what blackwater fish like. They are nice looking pieces though and may be good for a Guppy tank or a tank of other Livebearers as they prefer a higher pH. 

[grimms]

@Gator I'm just doing a freshwater tank with 1 betta. Would the pH eventually settle down if the tank is cycled long enough? Or will it continue to affect the pH as long as it is in there?

[StockEwe49]

I am not an expert in this type of stone but I think limestone will just continually breakdown? 

[Gator]

@grimms; They will affect the pH as long as they are in the tank. Bettas are blackwater fish originally from SE Asia, so your Betta would be happier without those decorations raising the pH in the tank. Those decorations do look nice though, do you have enough space to set up a Guppy tank to put those decorations into? 

[grimms]

@Gator No, I only have the 10 gallon tank to set up right now. I agree! they're so nice, but I'll have to do without them for now. I really like guppies so maybe one day I'll get them set up. Thanks for the info, much appreciated!