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Can someone help me understand what's causing my GH to increase?

Marcus_F

Member
Joined
8 Jun 2020
Messages
87
Location
Essex
Hi all,

I'm hoping someone can help me understand my water testing and identify what i'm doing to cause an increase in my tanks GH. Well I say increase as I'm fairly sure having read up (at a basic level) that my water changes are adding a much lower GH value of water than if I test the tank when full but let me go over my process.

I live in a very hard water area and took the decision because of fish to use a 50/50 mix of pure water and tap water. I use the API KH and GH test kits for all my values so even if they're not accurate, in reality using the differences between values should be.

My tap water provides me with a reading of 21 drops which I think is 375 hardness, I will stick to drop count before the colour change as I don't want to kid anyone that I know about water chemistry. I've checked and my pure water is pure and after 1 drop it instantly changes colour.
I tested my tank a few days ago and the reading was 21 drops for GH and still 6 for KH. This was a surprise as 21 is the same as my tap water but I've been using 50/50 mix for over a year now. So today I completed a water change and before adding the new water I tested it, the 50/50 mix had a reading of 11 drops for GH. I quickly tested the tank after the water change and GH was 18 drops.

So I'm asking myself what am I doing to increase GH?

Some details:
It's a 180litre tank
I dose liquid Co2, TNC Complete Lite and some Phosphate. I also mix in Magnesium Sulphate (MgSO4) into my new water and I'll add that my GH reading of 11 drops was before I mixed this in.
Fluval 307 cannister filter, have in last 6 weeks removed the carbon media and won't be replacing it.
I also switched from TNC Complete to the Lite version because my Nitrate levels went way too high could quite possibly be over 100ppm. Since changing to Lite I'm seeing a much better 20ppm Nitrate in the tank.

Hope that's not too much waffle which could be a fairly easy answer to one of the items I'm adding to the tank increasing the GH.

Thank you
 
Could be something or could be nothing but seen similar unusual readings and Caribsea Eco Complete mentioned in a few threads on ukaps. Perplexed about extreme TDS readings

Solution for now~ more water changes and add less gh... (that's what I'd do)... or...stop worrying about general hardness.
 
Could be something or could be nothing but seen similar unusual readings and Caribsea Eco Complete mentioned in a few threads on ukaps. Perplexed about extreme TDS readings
@Marcus_F @John q
I ruled out the Eco Complete by having a fair amount sitting in a bucket of prepped RO water for almost week. The rise in TDS was minimal if at all... My GH in the tank was never higher than 9-10 GH anyway.. What ultimately solved my "problem" with the extreme TDS was being more rigorous with my maintenance; 40-50% weekly WC (up from 20%), lower dosing of fertilizer (cut in half), using no abrasive (acid) chemicals when prepping my WC (water-change) water (essentially changing from 100% remineralized RO water to 50/50 Tap/RO Household water softener water usability and Equilibrium only - now changed to DYI Alternative to Seachem Equilibrium ?

I agree with @John q on WC. I would do two 50% net WC's a few days apart - just keeping your target at 11 GH for the WC water. After two 50% WCs your tank should read around 13-14 GH (assuming its now 21 GH). I wouldn't worry too much about any particular low or high GH level (unless its liquid rock or your particular fish or plants really really calls for it)... but rising parameters, in general, without knowing the reason should always, in my opinion, be a topic for some level of inquisition.

Also, do you have any rock/stone decor ? That may leach lime/calcium. If so, you might want to try and remove those if possible.

And what are you adding to the tank between WCs in terms of ferts and minerals ? and how often and how much are your changing when doing WCs ?


Cheers,
Michael
 
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Thanks all, I’m trying to isolate the rise as I think it’s having a direct impact to sick and then dead fish. Also using 50% RO water to get to the same result as my tap is kind of pointless so I’d like to get to the bottom of it.
My water changes are weekly and I change 40%. Tonight was only 20% as it’s the most I could do with remaining RO water I had stored and it was not a planned water change and I was only testing.

I’ll keep on with the 40% a week and keep taking readings as I had stopped assuming as I was completing regimented changes and dosing each week nothing would change.
I’m now reading up that magnesium sulphate can be used to increase GH. I add that to my regime after a recommendation to help my Anubis plants. Any fact in what I’m reading on the internet on MgSO4?
 
I’m now reading up that magnesium sulphate can be used to increase GH. I add that to my regime after a recommendation to help my Anubis plants. Any fact in what I’m reading on the internet on MgSO4?
@Marcus_F I wouldn't worry about Mg especially not for slow growing Anubias... unless your tank is completely depleted which is highly unlikely with this GH level - be it 11 or 21 GH... The best thing you can do for your Anubias is to give them shade... they absolutely hate intense light in my experience. My Anubias are absolutely thriving in my low light tanks. What do you use for remineralization btw.? You may want to check out this thread: Alternative to Seachem Equilibrium ?

Cheers,
Michael
 
I’m not adding anything to my water, it’s just a 50/50 mix with tap water. I only add TNC Lite, Flourish Excel and Phosphate. I will ditch the Mg for now and keep an eye on testing.

I don’t think I have any decorations leaching chemicals. Beach and garden stones only.
 
I’m not adding anything to my water, it’s just a 50/50 mix with tap water. I only add TNC Lite, Flourish Excel and Phosphate. I will ditch the Mg for now and keep an eye on testing.

I don’t think I have any decorations leaching chemicals. Beach and garden stones only.
@Marcus_F "beach stones" such as Dolomite rock contains a lot of limestone/calcium and if that leach out in the water it will register as GH. Perhaps you can post a couple of pictures of the tank and rocks in particular. I am sure some of the experts will chime on this if so ;)

Cheers,
Michael
 
Hi all,
I will ditch the Mg for now and keep an eye on testing.
unless your tank is completely depleted which is highly unlikely with this GH level - be it 11 or 21 GH.
It is a bit of strange one, but because of <"geological differences between the USA and N.W. Europe"> our hard water doesn't contain much magnesium (Mg), nearly all the dGH comes from calcium (Ca).
or...stop worrying about general hardness.
That is what I'd do. I'd just try differing proportions of tap and rain water until you find one where the <"plants and fish look happy">.

In terms of <"water parameters"> measure the conductivity and then keep the tank water within +/- 50 microS (30 ppm TDS) of that.
Beach and garden stones only.
I go on <"roundness">, if the rocks are very rounded pebbles or cobbles they will be inert, even if they are limestone, because only really hard rocks form rounded cobbles.
Caribsea Eco Complete, tank and substrate is 18months old
It could still be the soil <"via cation exchange">.

cheers Darrel
 
Thanks I will have a good read of those threads and update my knowledge. I'll only change one thing at a time and keep testing so I can understand how it's changing. Might stop the Mg for a while and test for a few weeks.
I think as I've not really monitored it's all a guessing game so I'll test a few times a week and keep track.
 
Hi all,
I think as I've not really monitored it's all a guessing game. so I'll test a few times a week and keep track
Yes, that is really the issue. A lot of tank water management has to be <"best guess">.

The problem with a lot of the water test, available to us, is that they aren't necessarily reliable or repeatable. I'm personally very interested in the parameters of the tank, but I also <"look after a lab.">, where <"we do some water testing">, and I understand <"some of the difficulties involved">.

It was those difficulties that led me to looking at <"other scientific approaches"> that weren't reliant on being able to accurately measure the chemical composition of the tank water.

cheers Darrel
 
I have Caribsea Eco Complete, tank and substrate is 18months old.
Hi @Marcus_F

It seems that Caribsea Eco Complete is as unpredictable as the British weather! Please take a look at this recent thread:


JPC
 
I ruled out the Eco Complete by having a fair amount sitting in a bucket of prepped RO water for almost week.
Hi @MichaelJ

That may not have been entirely representative of a tank setup. For example, 'prepped' RO water may be neither acidic nor basic, i.e. its pH may have been very close to 7.0. So, there may not have been any reaction between the 'prepped' RO water and the Eco Complete.

Just my two penn'orth.

JPC
 
The problem with a lot of the water test, available to us, is that they aren't necessarily reliable or repeatable.
Hi Everyone,

Just for the record, I have found many freshwater aquarium water test kits to be both reliable and repeatable. Darrel (@dw1305) and I simply hold different views on this topic. I suggest that anyone interested in using water test kits decides for themselves whether or not these are a worthwhile addition to the hobby.

JPC
 
Hi all,
Just for the record, I have found many freshwater aquarium water test kits to be both reliable and repeatable. Darrel (@dw1305) and I simply hold different views on this topic.
I'm not going to argue, it is <"horses for courses">. If people feel happy water testing, then test away. I definitely don't have any monopoly on <"successful tank keeping"> or aquarium water management.

Personally I'm not going to <"make decisions"> based on <"most test kit, or meter, results">, other than in a <"few specific cases">. This is the position I've come to over time and <"I'm happy with it">, if you aren't happy with it as an approach then I'd suggest you carry on water testing etc.

It is the same with <"tank cycling">, I'm happy with <"watch the plants and wait">, other people may feel happier with water testing until the test result tells them their tank is cycled.

For those who don't know @jaypeecee is a scientist and I think that if you follow the <"scientific method">, understand serial dilution and standard curves etc. you have a better chance of getting accurate figures.

cheers Darrel
 
What kind of fish?
And what happened to them?
What were the symptoms when they were sick?
@sparkyweasel I have quite a few varieties, the illness and death seems to be impacting the cardinal tetras the most. I've gone from 12 down to 3 over a 9 month period, I think losing 4 in the last 6 weeks and most of the time I've never even seem them ill or dead in the tank. I don't consider myself having a well planted thriving underwater garden but it's certainly getting harder to account for all the fish. I've also lost a few cherry barb, one black widow tetra and 3 harlequin rasboras and this is all over the same 9 month period. I'm being told many of these fish don't like the hard water hence why I'm using a 50/50 mix of RO water to drop the hardness and because my tap water has high nitrate.

If I do see the fish sick, they often find themselves in a peculiar state of laying on their side on the bottom or upside down and when they try and swim they complete an array of summersaults. It has all the hallmarks of swimmer bladder disorder but then could that be caused by the hard water, I'm not sure.
 
Hi Everyone,

Just for the record, I have found many freshwater aquarium water test kits to be both reliable and repeatable. Darrel (@dw1305) and I simply hold different views on this topic. I suggest that anyone interested in using water test kits decides for themselves whether or not these are a worthwhile addition to the hobby.

JPC
Thanks, I use the test kits with precaution as you say some people are skeptical however if they are showing off readings but you use the same test kit for all your testing, especially like me you're testing different bodies of water all at the same time, the results are not necessarily what is more important, but the range between the results. So my tank is showing GH of 21, water going in is showing GH of 11. If the test kit is whack and not giving a true reading, it will give the same whack for both tests in theory so the important takeaway is that the difference is 10GH. So even bad test kits can be useful.
I learnt this theory when taking cars to race tracks, handheld tyre pressure gauges are known to not be overly accurate however if you use the same gauge all the time, you know if pressure are up or down and the actual reading (which might be inaccurate) is not the important thing. I've no idea if this transfers to chemical testing but in my logical mind it should :)
 
and now finally for the photos of the tank and as best I can the rocks. I hope I'm not advised to remove them, the stones are the only input the kids had on the tank as they picked up from their holiday in Turkey :)

image0.jpeg image1.jpeg image2.jpeg image3.jpeg image7.jpeg
 

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