Rock help, slate and lava rock reacting?!

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Vladka

Aquarium Advice Activist
Joined
Dec 29, 2016
Messages
103
Location
Arizona
I’m preparing my 90 galling for cichlids and am adding rocks!

Issue: bought some lava rock and slate (I think) form my lfs for cheap, also bought some slate online for a little less cheap. The ones I got online I boiled, vinegar tested, and used the api nitrate bottle #1 and they were perfect. The ones I got at lfs, I boiled and tested and they’re all reactive! They also have a spot left on them at the site of testing. This is odd to me and I’m confused. Could there me something on them I need to work off? I also soaked in vinegar/water and scrubbed with steel wool (no real knowledge of why this would be effective) and they still react :(
Now I have pretty hard water, 7.8 in the tank and 8.3 tap. I don’t want to raise ph but why would this be happening? Also want to put the lava rock into my 29 gal RO water planted (ph is still kinda high in there too for some reason)

Side note: found some rocks camping as well, can’t tell if it’s phylogeny or petrified wood or what but they don’t seem to react and the bucket test showed they actually brought my ph down to 7.8 in bucket while control tap water cup went up to 8.4. I retested one of them and did see a little fizzing this time around, I’m very confused.

Question: so, should I clean them somehow? Did I misidentify? Are they safe to use?

Nitrate bottle 1 fizzy:
IMG_3761.jpg

Lava rock:
IMG_3760.jpg

Spot post test:
IMG_0002.jpg
 
You want the rocks to be there for buffering for harder water right?

The vinegar fizzy tests indicate that the rocks wouldn't be best in a community tank because they would raise pH because of the minerals in the rocks. I'm not sure what you need for the fish you have, but Cichlid additives to mineralize peoples water to be better suited for them is common, and these type rocks help you avoid or not need that as much. (From my understanding of most "Cichlids").

Also I would worry about boiling rocks and having them pop/ explode, for lack of a nicer word....
 
I just want them because they look nice and make good caves :)
I don’t want them to raise ph but I’m confused because these types of rocks are known not to raise ph. I have hard tap water, my tank is at 7.8 and tap is about 8.2 but I have some peat moss and wood and all that in the tank to help lower it.
I’ve always read that it’s important to boil rocks to kill off everything and clean them for the fish tank?
 
I do clean my rocks but with a only uses for aquarium stuff scrub brush, may have used baking soda or vinegar for cleaning but rinsed really well and soaked in Prime water, left to dry in the sun and turned over for sun drying.

Concern for found rocks would be industrial waste in rivers or lakes, gas or oils after floods being in the water way. Toxic spray from pest control like wasps (neurotoxin) or other insect or weed sprays.
 
Since you already have hard water (8.3 PH from tap) filling your tank with limestone wouldn't even raise the PH.
Water in my area is very similar to yours regarding PH. Over the years I've successfully kept many different varieties of Cichlids, including Discus, without adjusting water parameters.
Currently, the hardscapes in both my tanks mainly consist of honeycomb limestone. The PH
is not substantially altered. I think you have nothing to worry about.
Not a good idea to clean aquarium rocks with a steel wool scouring pad. Micro particles of the pad will get stuck in the pores & cracks. Relax a bit and enjoy designing your hardscape.
 
I’m still unsure about using these, the fact that they are known not to react and are reacting worries me. Which my tap water is very high at 8.3 id like to keep the water at 7.8 and one of my tanks uses RO water which is where I’d like to put the lava rock.
I guess I will bake them in the future instead!

The rocks I found were not in water just on a mountain. These rocks I bought I’m not sure why they’re reacting, I will not use steel wool in the future then. A few of them have been sitting in tap water and vinegar and have formed some oily looking bubbles on top of the bowl.
 
My pH tests out at 8.2 to 8.4 at any given time. I keep S.A. cichlids without issue. Fish adapt. It seems you are overthinking this a bit.

It's more important to know your KH, GH, and TDS
 
You can always use a few choice pieces of DW, may help in the softening process, which is better with more frequent, smaller water changes as to not remove all the tannins at a large pwc.

Also to get a better pH reading from your tap water, leave your tap water out for 24-48 hours and test.
 
I noticed you are using cleaning vinegar. You might test with white vinegar. It doesn't have as much acid. I don't know if this matters to be honest but most people test with white vinegar.
 
Rocks may have secondary alteration such that lava rock ends up with carbonate veins or coating from weathering or hot springs (in the past). This could be why they are reacting. Could be just from an unlucky spot in quarry, etc.

Rocks decreasing ph is harder. Rocks with any soil probably have organic acids that could decrease ph until exhausted. After that not aware of any rocks could lower ph I can think of.
 
I noticed you are using cleaning vinegar. You might test with white vinegar. It doesn't have as much acid. I don't know if this matters to be honest but most people test with white vinegar.



I actually didn’t realize that cleaning vinegar and white vinegar are different. I also watched a YouTube video saying that using the nitrate bottle 1 will be the same test as vinegar but have a much more noticeable effect.

I do also have driftwood in the tank, a pretty decent amount of it, and did test tap water for several days sitting there. It seems to be a little lower ph when treasured with prime. I have put all the slate into a bucket of prime after scrubbing with vinegar and then with water. Is there any chance the rocks are makeshift slate? I noticed a piece is broken off of one and it is light gray/white inside with only the outside being the dark gray color of slate. I’m not sure what the normal composition is but I thought it should be all a solid color.

My Gh and Kh are also pretty high, 15+ each. Maybe I should just buy a TDS test at this point, it’s hard to find a place that’ll test it and then actually make my way over there without forgetting a sample! I want the lower ph more so for the plants then for the fish, though I’m sure most the fish I have appreciate it too.
 
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