Help GH & KH doubling in two weeks

[tsmith_old_guard]

My office aquarium was planted 2 weeks ago. I did a dark start fishless cycle for 6 weeks. In the span of two weeks, my GH has doubled from 9 now reading 20 and my KH doubled from 5 to 10. (LFS tested my water and also confirmed the results) Does anyone have insight on the source of the increase in water hardness? The goal is to have a fully planted neocaridina shrimp tank. This fluctuation in water hardness will be a major problem for them. That being said, all the plants are doing great, growing well, transitioning to submersed forms, no algae problems at all. Additionally, the 13 Amano shrimp I put in the tank when it was planted have been thriving and growing (successful molts).



Aquarium Specs:

UNS 90u –74 gallon/ 282 liters

Displaced Water volume –53-55 gallons

Substrate:

Bottom layer/ back 50% of aquarium has Brightwell FlorinBase Laterin Substrat F, in media bags, with root tabs underneath (aquarium co-op root tabs).

Cap layer over FlorinBase and front layer: UNS Contrasand – TAHOE (pebble gravel).

Hardscape: Dragonstone and Driftwood –Driftwood is presumed to be native hardwood, it is not Malaysian driftwood or spiderwood. Sourced from Fish Gallery in Houston. Driftwood was submerged for 60 days before planting to waterlog and leach out tannins.

Fertilization:

Root tabs were placed in gravel where the substrate was planted. It was a 50/50 blend of Aquarium Co-op root tabs and Seachem Flourish Tabs

Liquid Fertilizer: 2HR Aquarist APT3, 5ml about every other day. I dose every other day instead of the instructed daily dosing of 5ml because 75% of my plants are epiphytes or slower growing crypt parva. Stem plant behind the large hardscape placements.

CO2: Pressurized with a reactor, drop checker reaches green.

Water Source: Home RO system with in-line remineralization filter.

Water Specs day after planting (06-15-2006):

PH: 7.4 -7.6

GH: 9

KH:5

NH3: 0

NO2: 0

NO3: 15 ppm (from post cycling water and APT3 dosing)

TDS : not recorded

Water Specs 2 week later (7-2-2026)

PH: 7.4 -7.6 (note green drop checker with CO2 injection)

GH: 20

KH:10

NH3: 0

NO2: 0

NO3: 20 ppm

TDS: 350



Any thoughts or suggestions? I was wondering if maybe I went too heavy on the root tabs and that was leaching into the water column? I was gernerous on the root tabs because I am using gravel instead of aquasoil. I don’t think the APT3 would be the problem. Dragonstone is supposed to be inert, and the UNS Contrasand TAHOE is actually pebble gravel and is supposed to be inert and not affect water chemistry, same with Brightwells FlorinBase Laterin Substrat F. All substrate was thoroughly washed and rinsed of dust. I think half the FlorinBase was dust, lol. Dragon stone was also soaked and thoroughly rinsed. IF all the hardscape and substrate are inert, then the source of the Magnesium and Calcium to double the GH must be coming from the root tabs or the fertilizer, right? Any, I appreciate the braintrust that is on Scapecrunch. Thanks for the input.

I do have access to pure RODI water from my LFS. I am going to do a 40% water change tomorrow with my home RO-re-mineralized water to not shock my Amano shrimp too much and/or my Bucephalandra and Crypts.



Thanks!

 

[Unexpected]

My understanding is dragon stone raises GH.

 

[Kwyet]

I’ve used, and am using dragon stone. I’ve never seen it raise gH or kH. I haven’t used Tahoe controsand, but I am using Mojave controsand. This initially raised both gH and kH significantly. Even now, 4 months later, it still raises both 3 degrees weekly after a 50% water change. I would be curious whether others with Tahoe have experienced similar effects.

Edit: I checked it on Amazon. The bag says that it slightly raises gH levels, which is the same warning as for Mojave. My experience was considerably more of an effect than “slightly” and it raised both gH and kH.

 

[SingAlongWithTsing]

which dragon stone?

ohko stone (tannish) or seiryu stone? (grey)

ohko is inert or very close to it. seiryu will raise kh.

 

[JayP]

which dragon stone?

ohko stone (tannish) or seiryu stone? (grey)

ohko is inert or very close to it. seiryu will raise kh.

I've never heard Seiryu stone referred to as dragon stone.

 

[Kwyet]

Seiryu translates as blue or azure dragon, so it is sometimes called dragon stone. Usually dragon stone indicated Ohko stone (a tan stone) though, which is inert. True Seiryu stone is illegal to export out of Japan, so what people buy for aquariums is actually Ryouh stone. Both Seiryu and Ryouh stone (grey/black stone with marbling) will affect water hardness. I was assuming OP meant Ohko stone.

 

[Capraquaria]

I would put a sample of your rock, and your controsand, into separate jars with water of known ph/GH/KH (ideally I would use distilled or RO water). Let the rock and the sand/gravel samples sit in the water a few days. You can check pH/GH/KH prior to adding your samples, and then retest every 24 hours to see if any of those parameters change. At least this way you can rule them out, or perhaps find which of them may be contributing to the increased hardness. Note that unlike some vendors, UNS makes no overt claims regarding their sand/gravels in regards to affecting water parameters. I experienced the same situation using a UNS controsand in a shrimp tank, and my GH/KH got ridiculously high between water changes.

 

[Capraquaria]

Edit: I checked it on Amazon. The bag says that it slightly raises gH levels, which is the same warning as for Mojave. My experience was considerably more of an effect than “slightly” and it raised both gH and kH.

Yep, Buce Plant warns that, too. "

• "Important Note: Controsand Tahoe may alter water chemistry by raising hardness. "

UNS Controsand - Tahoe

This item qualifies for FREE shipping to the contiguous U.S. Shipping to Alaska or Hawaii? Contact us for a custom shipping quote—we’re here to help!Ultum Nature Systems Controsand is a line of decorative sand substrates designed for use in planted aquariums and aquascaping. Tahoe is a rounded...

buceplant.com

 

[tsmith_old_guard]

which dragon stone?

ohko stone (tannish) or seiryu stone? (grey)

ohko is inert or very close to it. seiryu will raise kh.

It is the tannish Ohko stone, it is NOT seiryu.

Thanks everyone, it seems the Controsand Tahoe is the culprit. As and FYI on a google search had brought up Aqua Lab Aquaria page which says it's inert. However, I think this is the wrong statement and Buce Plant and Amazon have the correct warnings.

 

[tsmith_old_guard]

I would put a sample of your rock, and your controsand, into separate jars with water of known ph/GH/KH (ideally I would use distilled or RO water). Let the rock and the sand/gravel samples sit in the water a few days. You can check pH/GH/KH prior to adding your samples, and then retest every 24 hours to see if any of those parameters change. At least this way you can rule them out, or perhaps find which of them may be contributing to the increased hardness. Note that unlike some vendors, UNS makes no overt claims regarding their sand/gravels in regards to affecting water parameters. I experienced the same situation using a UNS controsand in a shrimp tank, and my GH/KH got ridiculously high between water changes.

Good idea, I was thinking about doing this as my next step, but it seems like the Contosand is the culprit.

 

[tsmith_old_guard]

I’ve used, and am using dragon stone. I’ve never seen it raise gH or kH. I haven’t used Tahoe controsand, but I am using Mojave controsand. This initially raised both gH and kH significantly. Even now, 4 months later, it still raises both 3 degrees weekly after a 50% water change. I would be curious whether others with Tahoe have experienced similar effects.

Edit: I checked it on Amazon. The bag says that it slightly raises gH levels, which is the same warning as for Mojave. My experience was considerably more of an effect than “slightly” and it raised both gH and kH.

This seems to be the case. I will start weekly water changes, which I was hoping to avoid in my office. I may have to breakdown the tank and replace the Controsand. I have A LOT of it. I am seriously thinking about doing this. If you have still having trouble doing 50% water changes after 4 months, this will be a difficult to manage as I am lugging 5 gallon jugs to change water in an office. I may just need to bite the bullet and replace the gravel. Thoughts???

 

[Kwyet]

This seems to be the case. I will start weekly water changes, which I was hoping to avoid in my office. I may have to breakdown the tank and replace the Controsand. I have A LOT of it. I am seriously thinking about doing this. If you have still having trouble doing 50% water changes after 4 months, this will be a difficult to manage as I am lugging 5 gallon jugs to change water in an office. I may just need to bite the bullet and replace the gravel. Thoughts???

I think replacing it would be ideal. The only reason I haven’t is that I didn’t want to waste the money I put into it, and I was hoping the effects would dissipate faster.

 

[Chimera]

Remember that these are all names for styles of rocks or gravels. A gravel by nature could contain a large mix of different mineral compositions and rock types. I googled "dragonstone" just now as I haven't got a local aquarium rock shop. Looks like it can be claystone, mudstone, lateritic material and any iron rich sedimentary formed material with a nice eroded puckered appearance.
Start with the ol "Scratch-and-sniff" only in this case scratch the rock or use a fresh gravel sample and put a little HCL on it. It's rudimentary but it will give you a field result or carbonate reactivity. This will not give you much on other minerals such as iron, but it's red flag.
If it passes the field test go to jar test with a sample in your aquarium water, which will likely have an acidic pH value.

 

[tsmith_old_guard]

Update.....

So, I emailed UNS product support, just to give them feedback on how bad the hardness leaching was from their controsand. They replied and long story short, they offered to replace my UNS Controsand Tahoe with UNS Controsoil. They offered this without me even asking, just asked for receipts, which I still had. They told me to go to the store I purchased the Controsand, show them this receipt, and I could get UNS controsoil bags as replacement. Here is the catch, I have to bring my gravel to the store and return it. I get it, they don't want people farming their return policy, but dang. I guess I will be showing up with 50 lb of used aquarium gravel in a few trash bags. I called the store, the manager is aware as UNS emailed them. Lol, I am not even sure I want to use controsoil, but hey that stuff isn't cheap!

@GreggZ @Chimera @Capraquaria @JayP

 

[Kwyet]

Wow! Now I wish I had done that, although I don’t think I could return it to Amazon now. Maybe if I had complained right away, lol!

 

[tsmith_old_guard]

Wow! Now I wish I had done that, although I don’t think I could return it to Amazon now. Maybe if I had complained right away, lol!

You should try it. It is not Amazon warranting the item, it's UNS. Send them an email with all the testing and water changes you have done. Amazon will have your receipts. They may just ship you a replacement through their Amazon store. I think your case is stronger than mine, you are still having trouble after months of water changes.

 

[Koan]

I guess I will be showing up with 50 lb of used aquarium gravel in a few trash bags.