Regarding live bearers/calcium

[Anthony]

Thanks for the time first off. I have a general question so holding off on pics etc..  Recently my beautiful black mollies stopped being active. When coming to greet me they sort of just waddled up to the glass surface.(nose up, tail down, and shimmying up instead of the normal swim behavior. I did dose the mollies 24 hours ago with Mardel Maracyn, and half a tble spoon of salt.  They are showing signs of improvement and swimming better already!

Did some research online. Ran into live bearer disease, and some causes. One which I think is the on going issue for my babies is the lack of calcium.  I have a water softener installed on the house. So I know they are deficient. I know they like hard water and will do well in relatively high ph. My tap water is in the 8.2 to 8.4 spectrum, Id like to add crushed oyster shells to the tank to get in some calcium for them.  I'm choosing this because I already have it for my chickens. 🙂  Also, because in my research it will just dissolve, letting me know when I need to insert more.

My concern is the effect it will have on my ph.  My mollies are fine where they are ph wise, but I have no idea how high or how fast the crushed oyster shells will send my ph, or the affect on my fish if the ph goes north of 8.4? I am looking for some advice on how best to proceed with adding some calcium via the crushed oyster shells.(unless there is an easier/safer method)  Also, if I am on the right track here, how much would I put into a 20L with 8 black mollies?  I have to find a way to get the calcium into my tanks with live bearers. Please help. Thanks again.

[Colu]

I have used crushed oyster shells in the past what I did was add a small amount in a media bag in my filter gradually increasing the amount 100g raise my pH from 7 to 7.5 didn't seam raise my GH and kH much 

[Anthony]

Colu, Thank you for that info. I have a scale and a media bag! Thinking of doing a water change tomorrow on them. Adding some RO h20 to lower the ph a little, this way when I add the crushed oyster shells I won't send the ph above 9. 🙂 Im thinking I have a plan now thanks to you.

[Colu]

I would start with 50g and see what affect that has on your pH then increase the amount as I have lower pH in my tank so it might have a different effect on your ph

[Anthony]

Thank you. Will do.

[Hobbit]

15 hours ago, Anthony said:

My tap water is in the 8.2 to 8.4 spectrum, Id like to add crushed oyster shells to the tank to get in some calcium for them.  I'm choosing this because I already have it for my chickens. 🙂 

Hey there fellow chicken keeper! I also used crushed oyster shell for the same reason. 😊

I’ve found oyster shell dissolves very slowly and gently. I have super soft tap water and oyster shell doesn’t raise my KH or PH as much as I need. (I actually bought crushed limestone to mix up and add directly to the water.) Since your pH is already high, I don’t think it’s likely the oyster shell will change your pH much, but it’s still a good idea to put it in a bag just case it does more than you think and you need to take it out.

I do worry that because your pH is already high, the oyster shell may dissolve even less and not release enough calcium for your mollies. You could try grinding eggshells into a powder (as fine a powder as possible) to get calcium into the water faster. I tried just adding crushed eggshells to my water and it did nothing, but I think a fine powder would do much more. Eggshells and oyster shells are made of the same stuff, but eggshells are a lot easier to powder. 😁

Edited May 13, 2021 by Hobbit

[Anthony]

Hobbit, Thank you for the advice and information. Good to know I am not the only fish/chicken dude out there! 🙂 I do have crushed eggshells from my chickens of course lol! Ground them up months ago with my coffee grinder, and stored it in an empty fish food container. Just totally forgot I had that as well. So thank you for contributing to my thread here and reminding me. Regarding the crushed O shells effectiveness due to the high ph, I decided to add O R h20 on a 75% water change last night to bring the ph down closer to neutral, thus raising the roof for ph to rise after adding the crushed oyster shells. So I am off this morning to begin the process of slowly acclimating in the crushed oyster shells w/ readings in between.. I will probably update here later on my findings for reference. Thanks again.    

[Hobbit]

Sounds like a great plan! Glad I could help.

[Anthony]

Update: So 24 hours from adding RO water I took ph readings. Definitely cut my ph down from 8+ to  around 7. I then added 100 grams of crushed oyster shells with confidence 🙂 . 1 tbsp averaged out to 20 grams. so 5 tbsp worth. I used a digital scale.  Approaching between 36 and 48 hours I took another ph reading,  and sure enough the 100 grams seems to have bumped me up to 7,5! Went ahead and tested the Calcium CA2+ with API test kit, if I am reading the color right I am at about 220ppm.  I can live with that even if its a little more than it should be. As it will slowly dissolve. I have another tank where I did the same but I must have gone heavier on the COshells. Same size tank, with about 12 Goodea Lyonsi, measuring 520 ppm CA2+. Should I leave it or dilute that? Thanks again Peeps.  

Edited May 19, 2021 by Anthony