Dh/gh/kh Confusing

  • #1
I have a GH/KH test kit.

GH takes 5 drops to change, which = 89.5 ppm (soft water)
KH takes 3 drops to change, which = 53.7 ppm

Is my understanding correct so far?

With soft water I need to have fish for soft water (angelfish, ram, apisto, tetra along those lines)

When I try to research the fish to find what fits soft water, for example seriouslyfish will show hardness in DH. Example dH 5-10 or dH 0-12 means what in gH.

What does my kH reading mean to me? Will I have problems with keeping pH balanced?

I'm so confused lol
  • #2
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  • #3
Thank you for replying, I have already read the link you provided (had it bookmarked in fact) and it still doesn't answer my question lol.

I have read lots of other folks comments, some stated that fish can go from soft to hard but not hard to soft, Mollies for example will only live about 6 months in soft water, then die of organ failure. Dragones5150918 wrote the analogy I read, it was very good. I have also read good info from CindiL

Anyway check back in a couple hours, have errands to run.
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  • #4
Still looking for answers lol


Good Morning, trying again today
iZaO Jnr
  • #5
Thank you for replying, I have already read the link you provided (had it bookmarked in fact) and it still doesn't answer my question lol.

I have read lots of other folks comments, some stated that fish can go from soft to hard but not hard to soft, Mollies for example will only live about 6 months in soft water, then die of organ failure. Dragones5150918 wrote the analogy I read, it was very good. I have also read good info from CindiL

Anyway check back in a couple hours, have errands to run.
Although I wrote that a very long time ago, it still does apply to your issues here.

While some folks may so that freshwater fish cannot go from hard to soft, this is not entirely true, particularly for the example you mentioned being live bearers.
Freshwater fish live in circumstances where water bodies change in volume regularly, so of course the water parameters change accordingly.

The osmotic balance of a fish's internals (organs, blood, skin, etc) is determined by the pervading environment. It is easier for a freshwater fish to control what solutes (things that will determine you water's hardness) ate taken up, as opposed to saltwater specimens who live in the extreme reality that they have to take these things up due to there being an over abundance of solutes in marine water. To summarize, most freshwater fish can adjust very well. The ONLY serious group of fish to be an exception IME is the African Rift Lake species, especially tanganyikans.

As for your issue of conversions and the likes, see this link

Hardness convertor
  • #6
I'm sorry for walking into this so late Kataira. The bat single never went off to let me know if was mentioned. Hopefully I can come up with the answers you need. CindiL is on vacation, so it's hard to get ahold of her.

The dH means degrees of hardness. When you use your KH/GH test kit, each drop is considered a degree. So your 5 drop test of GH is read as 5dGH or 5dH (5 degrees of hardness) so when you get a wide range of dH, means that fish can adapt to a wide range of hardness....though I do not know if any fish that can live in 0dGH.

3dKH is pretty low, and not really suitable for cycling a tank....Unless you monitor it daily and raise it up when the KH and ph falls. Depending on size of tank, you can actually maintain a 3dKH and not loose your cycle. If say you have a 30 gallon with just a school of Rummynose Tetras, and nothing else, completely cycled, you can go with 3dKH and not really loose your PH or much of your kh. Now say you have a completely stocked tank of Cardinals, Rummynose, rams, and cories, you could not maintaine your PH or your kh at 3dKH. Your cycling bacteria will eat it all up quickly which will cause your PH to fall. Fish do use a little kh, but it is mainly the cycling bacteria that use it.

You can actually increase your kh with out effecting your gh by using products like Alkaline Buffer or Kent Supper Buffer for salt tanks. Those products will only increase your kh and if used to much also effect ph. They will do nothing for gh. If you want to increase both, you can use the Alkaline Buffer and Replenish, or use things like crushed coral, aragonite, limestone, etc. If you just want to increase your gh and not kh, then just use Replenish.

If you really do not want to mess with your KH and GH, you actually have the right water for a Black Water tank set up. Black water tanks are nothing like a standard tropical tank. It does not use the same bacteria. The bacteria we use or our tanks need a good ph, kh combo, and they can not live below 6.2PH and need a good amount of kh to multiply and do their job. Black water tanks are totally different. They are normally 6.0 or lower in ph, 0 to 3dkh, and 0 to 5dgh. They use peat moss in the filters, almond leaves as a cover of the substrate, lots of driftwood, and maybe a few plants that can handle low light. As for bacteria, we'll I do know stability and tss+ bacteria can't live in that. I do not know much about black water tanks, and the information I've stated is the extent of my knowlage, but that is an option you can use when setting up a tank with your kh and gh.

Hope the info I've given has helped.
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  • #7
As for your issue of conversions and the likes, see this link

Hardness convertor

iZaO Jnr
Thank you so much, I had seen several convertors but they didn't seem to be what I was looking for. This is perfect
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  • #8
Thank you, what you said is what I was thinking was happening, but I wasn't sure what to do about it or if I needed to do anything.

Now lets throw the pH I have into the mix. With the GH & KH readings I have, I should have low pH, but I don't. I use the API Master to test with, when I test pH it is blue, which is 7.6. So then I test with the high test and it's light brown/tan which is 7.4. So I'm guessing I'm somewhere in the 7.4-7.6 range? I even bought the Tetra EasyStrips to see what they showed lol, which was a waste IMO.

My test straight from the faucet the first time I tried testing was pH 8.3 : Ammonia .25-.50 : Nitrite 0 : Nitrate 0 : KH 3 drops=53.7 ppm : GH 5 drops=89.5 ppm
I'm better at reading the results (I think) so going to retest the tap later today. I also read that I needed to let it sit for a while before testing.

I set up a 10 gallon with sponge filter/heater/bubble stone (future quarantine tank) to float the plants I've bought. I also treated it with prime and stability to get the cycle going. I also put those white ceramic things from the canister in there to hopefully get bacteria on them. This is the tank I've been testing on. It has cycled, last test was PH 7.5 : Ammonia 0 : Nitrite 0: Nitrate 10. I have seen a few snails that came in with the plants moving around. On Friday afternoon we added 2 male guppies, so far so good. Will test again this afternoon.

End goal is a 75 gallon planted/community tank

Setup so far:
75 gallon 48x18x21h Marineland
Marineland Magniflow 360 Canister Filter
Pro Heater 250W
Current USA Satellite Freshwater LED Plus 48-60

45-50 different types of plants floating in 10 gallon
4 pieces of driftwood soaking for 2 weeks now
1 piece of lava rock
slate. We have been putting together a slate structure, just got it finished and its done curing.
bag of misc river rock
eggcrate for bottom
40lbs Eco-complete
50lbs BDBS
API Quick Start

We are finally going to put it all together today, I'm so excited.

As far as fish, I have always wanted angels, which I think I'm perfect for, so list so far is:
Diamond Tetra
Pearl Gourami
GBR or Krib
Hubby wants loach (Polka dot, Yo-Yo, Zebra or Chain) I talked him out of the Dinosaur Eel lol. thankfully our tank is not big enough

I know that once I get the 75 up and running, some of my number can change based on what is in the tank.
My GH should be good unless something drastic changes it. What would be my ideal goal for KH? I think I read somewhere a min of 5 KH does that sound right? To raise just KH I just need the Alkaline Buffer, but how will that effect the pH and do I need to worry about that.

I just want my fish to be healthy, not interested in creating ideal breeding situation but if it happens I can always move them to another tank.

Thank you so much for your time, I just want to get it right as best I can the first time.

  • #9
Sorry, I was out buying things pretending I had money, which I don't. lol. Unfortunately none for my tanks either. I've been avoiding the pet shops like they have the plague, otherwise all the money goes into my tanks. lol

OK, on to your post. One that that sent up the warning flag is those 2 guppies in the low KH water. Live Bearers generally need 8dGH to 12dGH for their osmotic process. In general, live Bearers need more minerals then a tetra in their water for their osmotic balance and process. OK, I put that wrong. Not more minerals, just a higher concentration of it. So they absorb more minerals such as magnesium, Zinc, etc so you need a higher concentration of it. Think of it this way....to put it in human terms. Live Bearers, cichlids, and gold fish need hard water....like a child needs a higher amount of vitamins. Most fish on the market need a decent amount of hard water....Like adults need a decent amount of their multivitamin. Soft water fish such as tetras, angles, rams etc would be like senior vitimins. Now not taking dietary into account to supplement of vitamin and mineral needs of the human body, just the vitamin pills. A child will have health issues if the child solely used adult or senior vitamins. The possibilities of health issues would be huge, from a weakened heart and bad circulation, to liver and even brain disorders. Stunted growth even. Now take the opposite side. A senior can take a childs vitimin and suffer really no ill effects. Their body will absorb only so much and expell the rest. In other words, rehome the guppies or bring up the gh for them. Even though right now they are doing fine, later on down the road, they will start to show the effects of the low gh. Hope this makes sense to you.

On to the other items. The ph straight from your tap is 8.3, which is about average, but after it being I your tank it drops to 7.4, if I understood correctly. This is out likely not a kh issue. You would see a drop in your kh if it was. It is more likely the additives they add to the water that is the problem. To make sure that is the problem, would you please take a glass jar or a cup, fill it with water, take a ph reading, then aerate the water using an air pump and a stone. After an hour, test the ph and write down the results. Retest again at the 2, 12, and 24 hour marks, and then post total results.

As for ideal kh, I would.suggest no lower then 5dkh, higher preferred while cycling, then between 4 and 5dkh after your cycle and fish are added in. After a week, with a fully stocked tank, your kh should drop a degree or two, so I would go more with 5dkh to be on the safe side.

Off to go harass my husband as he does house fixing for me. Muhahahaha
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  • #10
Dragones5150918 That's ok, I spend all my time looking at all the pretty fish I want, and trying to decide what I want the most lol. We have been busy putting the 75 together, still not done, will do the plants tomorrow. Not sure what time I can start the pH test, we have a German Shepherd that needs to go to the vet. Kids and pets always get sick on the weekend lol.

Going to go ahead and order the Alkaline Buffer unless you think I should wait til after the pH test is done. And told hubby the guppies had to go back.

Thanks again
  • #11
I would go ahead and order the Alkaline Buffer, and when you can do the water test. I'm pretty sure that is why your PH dropped was because of the additives, not because of kh.

I know how life is, trust me. I've hardly been home today between dropping my adult kids at their job, hitting different stores, doing things around the house, then getting kids at different times, and so on. Yep I do know. Good luck!
  • #12
The actual test kit instructions provide a range

GH & KH Range Aquarium Life
0º - 3º Discus, Arowana, Elephantnose, Neons, Cardinals, Live Plants
(0-50 ppm)

3º - 6º Most tropical fish including Angelfish, Cichlids, Tetras, Botia, Live Plants
(50-100 ppm)

6º - 11º Most tropical fish including Swordtails, Guppies, Mollies, Goldfish
(100-200 ppm)

8º - 12º Marine fish and invertebrates
(140-200 ppm)

11º - 22º Rift Lake Cichlids, Goldfish, Brackish Water Fish
(200-400 ppm)

I'm not sure why Goldfish are included in two groups without any distinction.

In the event that using a buffer increases your pH you can use (as recommended by Seachem) both the Seachem Alkaline Buffer and Seachem Acid Buffer to specifically target a pH and kH.

Seachem - Alkaline Buffer

Navigate to the Calculator tab for specific kH (must convert to meq/L first there are websites that do this) then back to Details and divide by the number in the middle column and that will determine the amount of acid buffer required

Additionally you can download their Dose2 App which is really good.
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  • #13
Aquaboy Thank you for the additional info.
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  • #14
Dragones5150918 Finished the water test this morning. I tested both pH and High Range pH. The first reading is pH and the 2nd is for the High.

0 hour 7.6 / 8.4
1 hour 7.6 / 7.6-7.8
2 hour 7.6 / 7.4
12 hour 7.6 / 7.4-7.8
24 hour 7.6 / 7.4-7.8
At the 24 hour mark I also tested
Ammonia 1.0+ We could actually smell the chlorine in the water yesterday, it's not usually this strong.
Nitrite 0
Nitrate 0
KH 3
GH 6

On the high test the color is like a light brownish/tanish color, its lighter in color then the 7.4 color chart, but I don't really see any orange tint to it.

We also got all the water added to the 75 gallon last night (treated with prime). All the decor has been added, and over 70 plants. Everything was done except turning the canister on. I tested the 75 gallon tank also, (before we turned on canister). Here are those readings as well.

pH 7.6
High Range pH 7.4-7.8 the same light brown/tan color
Ammonia .25
Nitrite 0
Nitrate 0
GH 5
KH 3
We also have a swimming pool test kit, so I used that also to test the pH and it showed <7.6
I think we are running somewhere in the 7.5-7.6 range.

The alkaline buffer should be delivered any time now.

The canister is up and running now, temp is set to 80 degrees.
So far we have treated the 75 gallon with Prime and Stability.

Thanks for all your help
  • #15
Yeah, it sounds like the additives are in your water. For now on aerate any watet your going to use for a few hours to get the ph down to its natural level for your area (7.6). Going from 8.4 to 7.6 in a few hours is to big of a swing on fish and can cause ph shock. I have to aerate my water as well in 5 gallon buckets, then I add between 1/2 and 3/4 of a teaspoon of alkaline buffer to each bucket and do my water change. That gives me about 5dKH with that amount. If your using 5 gallon buckets, start with 1/2 a teaspoon and test your kh. Once you hit 5dKH stop and do your water changes.

If your going to have live bearers, you'll need to increase your gh. Otherwise your gh looks good at 6 degrees. Works for most fish.

Looks good to me your test results. Keep us posted on your progress.
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  • #16
Dragones5150918 Yes I do use 5 gallon buckets, so add the 1/2 teaspoon to each bucket, then test after I finish the water change, after all the buckets are added back in, not each bucket right? The Alkaline Buffer was just delivered do I go ahead and treat the 75 tank now? I will have a little bit of trial and error period while the tank cycles to learn how to get the numbers correct and stable before I add fish lol.

As far as the way the buffer works, once the KH in the tank is at 5 then the only time I will add more buffer is with the water changes, correct? I shouldn't have to monitor the KH in the tank daily or anything?

At some point with a planted tank I will need to start using I think Flourish, will that effect any of the numbers?

As far as fish, I'm staying away from the live bearers (for now anyway), I will be going with soft water fish like angels, rams, apisto, pearl gourami & diamond tetra is what we are looking at so far.

Thanks again
  • #17
Great that you got it.

On, one bucket put in about 1/2 teaspoon in, stir it, and then test it. If the KH is not at 5dKH, add 1/4 teaspoon more, restore, and retest. Once the bucket makes at least 5dKH, then you know how much you need to add to the other buckets. You may want to bring one bucket to 8dkh, which should be a full teaspoon, because your tank is at 3, and with a 50% water change using 5dkh plus one bucket at 8dkh, should set your tank at 5dkh by the time your done with the water change. Make sense? That is if your using the water change to increase your kh.....while cleaning your tank.

If you just want to increase the KH with out the water change, I would get a cup of tank water, add about a tablespoon of alkaline buffer to it, stir, then every 15 to 30 minutes, add a quarter of that. Once it's all in, wait about 10 minutes and test your kh. You should be around 5dkh. If not add a little more until you reach 5.

Flourish will not change your kh or gh. It can increase your nitrate though, so please do not over indulge in the use.

That stock sounds good for your gh. I would say get them. Could I also suggest maybe some other schools like Cardinals or Rummynose Tetras? I have them in my tank and just love them.
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  • #18
Dragones5150918 I think I got all that lol. I'll get the current water in the tank to 5 then when we do a water change next time we will adjust the buckets.

I was actually considering Cardinals or Runnynose, last night hubby said he wanted swordfish, and I was like nope can't have those lol, so he asked about Cherry Barbs, I have to research them still.

Just taking this process one step at a time, I'm sure I'll have more questions as we go along

You have been so helpful
  • #19
Barbs can get a little aggressive in a peaceful tank, and can nip at flowing fins so you'll have to watch the angles. Depending on how many fish you put in your tank, you could get away with Barbs if you have enough plants to break line of site. Your tank is big enough. As for parameter compatible, I have no clue. I do not know much about fish stocking, except fish I've had, and I've had Barbs, and they nipped my angles fins.
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  • #20
Dragones5150918 I was afraid they would be fin nippers. He also likes the botia loaches like PolkaDot, YoYo, Zebra or Chain ever had any of those hehe. I was going to make a post later on in the stocking thread to see who might have experience with any of them. Have lots of plants but they still need to grow, I'll take a pic when all the little bubbles go away, the canister is still spitting bubbles >.<
  • #21
My husband loves the Dojo loch. They are pretty funny fish. They are also know as the barometer fish, because they get really active when the pressure changes. Lochs can be escape artist, so a good lid is needed.

Definitely post for suggestions for your tank. I can't wait until you post pictures when your done with it.

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