diy rock problems??

smallfry

Member
I made lots of DIY rocks using potland concrete and crushed oyster shells. The rock has been curing in fresh water with the water changed every 3-4 days for 7 weeks now.
The problems are :
1. In two of the buckets the water and the rock are getting a very bright green algea on them.
2. The PH is still off the charts shouldn't I be seeing some lowering by now?
Thank you for any input.
Janet
 

smallfry

Member
I found several infromational threads on this subject here on SWF.com.
You can use what ever you can make a mold in with sand. I used any thing from a cooler to plastic shoe boxes, anything or every thing. I wanted to be able to make as much in one days as I could because they need to cure in the sand for 3 days.
You will need sand for making molds.
potland type II concrete, found ours at home depot.
crushed oyster shell, found ours at a feed store.
bucket for mixing concrete mix, I used one of my 5 gal buckets used for water changes.
I used rubber gloves to mix mixture.
The basic mix is 1 part concrete to 3 parts oyster shell 1 part water.
I have seen other portions but I found this to work well.
So depending on the size rock I was making I would mix it up. Put into a mold in the sand and let sit for 3 days. remove let cure in the sun and make more and repeat and repeat until I used all my crushed oyster shell.
Like i said there are some threads that have photos and all. Look them up.
It was a lot of fun to make I just hope it work out in the end.
Good luck
 

psusocr1

Active Member
i know your supposed to do water changes EVERY day , ic an imagen that could be a problem, also alge blooms can be due to any light especially sunlight hitting the rock?? where do you keep the rock at? i also rread that depending on your ratio of cement to shells etc. it can have an impact on how long it takes for the PH to go down
 

celacanthr

Active Member
actually, I have had a problem with this also. But that was in my first batch. In this last batch, I haven't been in a hurry to get the rocks, so I have taken a very leasurely pace. Whenever i think about it, I will empty all of the water from the trach can I am using,a dn just let the rocks air dry, adn then the next time i remember the rocks I fill the trash can all the way up with extremely hot water (as hot as you can get from the tap). This time around the rocks seem to be stronger than last time, but i could just be imagining it.
HTH
 

smallfry

Member
psusocr1
Its funny that the bucket that is not in the sun is the one getting the algea.
According to what i have read on this site you were to leave them in the water for 3-4 days and that changing it any sooner does not speed up the ph drop.
CELACANTHr

I have let the rocks with the algea bake in the sun and the algea seems to be dissapearing. I think i may just let them dry out in between water changes and see if this keeps the algea away.
Just more waiting lots of that in this hobby.
Thanks,
Janet
 

thangbom

Active Member
you are right about letting them soak in water for 3-4 days then do a WC. but the amout of water the rocks are soaking it matters too. it's kind of the same principle with a larg fish tank and a small. once the polutants from the cement is difused out of the rock and saturate the water, the rock cant 'cure' any further. thus a WC. the larger the volum of water, the more polutants can difuse out of the rock and into the water. The ratio of cement,shells and argonite sand also play a role in how long it take to cure the rocks. the cureing time is based on the amout of Cement used. the cemecnt is what contaions the polutants thuse the more cement used, the longer the cure. as for the algea, that is due to a light source. no light = no plant life. and just a note, once the ph is good from curing in freshwater, you need to then cure the rock in saltwater, this will cause a minor ph spike agin. you just repeat the same steps as the freshwater cure.
gl
 
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