Hi Rob,
Can you address general hardness and carbonate hardness and how they relate to each other and a stable pH? Try as I might, I can never seem to get my reef pH much above 8.1. I use Seachem Marine Buffer but still can't attain, let alone maintain, a pH of 8.3.

Thanks,
<Mark />

u want to take this one rob, it is for your calling amyways..lol

go for it, im not very good at explining this stuff, which is why i have not covered it on a show.. :)

i can , but not now, im about to head to work> seems i live at the place these days! anyways, we have knowledgeable people here, should get an answer!
but if not i'll write a wicked piece up tonight, & even give u crappy write laws so u can chop it up for a show ok rob:p

Try as I might, I can never seem to get my reef pH much above 8.1. I use Seachem Marine Buffer but still can't attain, let alone maintain, a pH of 8.3

Ditto this. The highest I ever got was 8.2, now I am back down to 7.8.

GH(general hardness) is a measure of ALL dissolve minerals. KH is a measure of ALL dissolved carbonate and bi-carbonate minerals. it is only the carbonates and bi-carbonates that act as a buffering compound to maintain a proper high pH in a marine aquarium. GH in a marine tank will be 12-18, and KH 9-12. GH tests have very little use in a marine enviroment execept for RODI water since it will test all mineral dissolved...indicating polar activity between ions, leading to a test known as conductivity.......which leads to a measurable test called TDS(total dissolved solids).

sweet. who said u dont learn something everyday!i did not know this:p thanks blubber

GH tests have very little use in a marine enviroment execept for RODI water since it will test all mineral dissolved...indicating polar activity between ions, leading to a test known as conductivity.......which leads to a measurable test called TDS(total dissolved solids).

So... if I have a TDS meter and I am testing my RODI water, are you saying that I don't even need to be testing for general hardness?

So... if I have a TDS meter and I am testing my RODI water, are you saying that I don't even need to be testing for general hardness?
yes, you have no need to test GH. i us GH test only because i have freshwater tanks too.

This is good information, but how does this help me to attain, and maintain, a pH of 8.2? Maybe I'm reading your answer correctly.

This is good information, but how does this help me to attain, and maintain, a pH of 8.2? Maybe I'm reading your answer correctly.
is your KH 9-12?

I just got my KH kit today, my reading was 16.

have u been using some kind of buffer?

Yes, as I mentioned previously, I have been using Seachem Liquid Marine Buffer, just like mvcg2001.

Yes, as I mentioned previously, I have been using Seachem Liquid Marine Buffer, just like mvcg2001.
okay. i missed that. i read quickly and thought you said you were using Seachem Marine Salt. do you have a calcium test result?

Yes. My Calcium is high, 580

that was what i thought. i have never used that buffer before, but it seems like it may contain a lot of calcium. stop using that buffer. what salt mix do you use?

The Seachem Liquid Marine Buffer says it works using Carbonite, Bicarbonate and Borate Salts. Those are the only ingredients listed.

As far as the salt mix, I began with Oceanic. When I am done with that (soon) I already have a 5 gallon bucket of the SeaChem Reef Salt ready to rock and roll.

okay. if an aquarium shows high KH and high Ca reading at the same time while reading a low pH, i think that indicates poor gas exchange. what was the pH, KH, and Ca readings of the new change water? you must know the parameters of the new water before you can make changes to the tank water.

I have some pre-mixed RODI water available, and will try to take some readings this morning. I will post them here.

Do you want pre-salt mix or post mix readings on my RODI? I am guessing only after it has been mixed. When I mix my salt, I measure everything specifically, actually bring it to temperature and run power heads on it for 1-2 days. I mix 7 gallons at a time.

I Currently have a 29 gallon tank, 2x270 GPH aqua clear powerheads and a fluval 180 GPH cannister (no flames about the fluval, bought it from a less than reputable LFS before I knew what the hell I was doing, have removed all media except carbon and replaced with LR rubble). This leaves me with a total circulation of 720 GPH, about a 25x turnover rate.

Sorry... mvcg2001 if you feel like I am hijacking your thread, let me know and I will start my own. Hopefully we are having similar problems, I never even thought of it that way.

GH in a marine tank will be 12-18, and KH 9-12. GH tests have very little use in a marine enviroment execept for RODI water since it will test all mineral dissolved...indicating polar activity between ions, leading to a test known as conductivity.......which leads to a measurable test called TDS(total dissolved solids).

Great thread guys, I thought I knew most of this, but I am picking up new info as well!. One questions, A GH test will not replace the need for a TDS test in RODI? Meaning, if I test my RODI for GH, I don't need a TDS meter.

This is my newbie guess... but since you have to measure TDS to gague the effectiveness of your RODI system, the general PH test would not replace the TDS meter.

You must know the parameters of the new water before you can make changes to the tank water.

Here it is: my RODI water with the appropriate amount of marine salt:

pH: 8.2
KH: 6
Calcium: 360

We have pretty hard water around here.

No worries JeffDubya. I'm learning as we go. I'll test my water and get back.

Um... my KH test kit gives me 120 mg/L CaCO3 (Calcium Carbonate). Anyone know the conversion so I get a nice clean number like JeffDubya's. What is your measurement unit JeffDubya? Until I know how to convert, we're not talking the same "language".

My Ca tests 200 mg/L, low for a marine tank. Given that, I know I have to raise my Ca to 400mg/L.

Assuming my KH is good, anything else I'm missing? What about the pH of my replacement water (RO)? My be a dumb question, but does that have to be buffered too? I've been assuming it doesn't.

<Mark />

Will Seachem Marine Buffer raise my KH too, or just the pH? If not, what do people use to raise KH?

<Mark />

Let me clarify the previous, apparently "stupid" question. Per Rob's podcast on Kalk, Kalk helps to *maintain* pH and Ca levels, but doesn't actually raise these levels, right?

I've been doing some reading and ran across this statement, "Use [SeaChem] Reef Builder™ to raise carbonate alkalinity without affecting pH. Use [SeaChem]Reef Buffer™ to raise carbonate alkalinity and pH." Is anyone doing this and how is it working? Any tips?

<Mark />

kalk "can" be used to raise Ca and Alk together, but i didnt go into it as its a more advanced trick.

as for raising Alk, you can use one o the buffers mentioned, or you can use plain old baking soda.. :) the primary ingredient in both the products is sodium bicarbonate and can be used to raise Alkalinity

Was a post of mine deleted? I seem to recall making a post which is no longer there.

I hope there was no misinterpretation... mvcg2001 I never insinuated that anything you posted was stupid. What I did was preface *my own* comment with that disclaimer, because there was a chance, as a new reefkeeper, that I was completely wrong in what I was posting.

I've been doing some reading and ran across this statement, "Use [SeaChem] Reef Builder™ to raise carbonate alkalinity without affecting pH. Use [SeaChem]Reef Buffer™ to raise carbonate alkalinity and pH." Is anyone doing this and how is it working? Any tips?


Yes, that is their product. I had purchased a bottle, but I took it back this weekend, because:

(1) My kH doesn't NEED raising

(2) Like Rob said, most people I have been reading on this and other foums just use baking soda, which is significantly cheaper.

No misinterpretation JeffDubya. I was calling my own question stupid. :)

I was in reference to the question of "What about the pH of my replacement water (RO)? M[a]y be a dumb question, but does that have to be buffered too? I've been assuming it doesn't." I'm not clear if the evaporating water also evaporates whatever keeps my pH high. (Yeah, I'm this old and don't know that stuff. How much money did I waste in college anyway?! :madmad: ). You know, like salt doesn't evaporate but only the water. When you replace evaporated water you don't replace the salt.

<Mark />

Okay, time for my own confusing addition to this discussion :)

From what i learned in the discus fields, KH and pH are directly related. Raising or lowering one will result in the other following suit. Thus, raising pH alone should raise KH as well, although how far i am not sure. I have found this to be true with my discus water: if i add some of the ph Down stuff, the KH drops to about 1 or 2 (this is the opposite of a marine tank :) ). Thus, my guess is this. If you use baking soda to raise the pH, which i have never thought of btw, it should raise KH as well. Given that baking soda is a bicarbonate, this makes perfect sense.

High KH buffers against pH fluctuations, and a high KH should also result in a higher pH, although i am not sure how tightly the two are linked (i.e. i dont know if raising the pH by .5 equates to a KH increase of some #, it might be more ambiguous than that). For example, i do not think it would be possible to have a KH of 7 or higher and a pH of 6.0.

But, one final question for the baking soda idea. How much do you use? I dig this idea, i was about to post asking about the drops, but this seems a more "natural" approach.

Astrivian - not arguing with you, just trying to understand. Based on your argument, why isn't my pH high? My dKH is 16, recommended (as near as I can tell) is 12. But my pH is only 8.2 and I have to WORK to get it that high!!

My first guess would be the salinity is too high, because I easily notice that corrrelation. RODI pH is 8.6, mix with salt, down to 8.2 like clockwork. My gravity is 1.026 instead of 1.023. I am trying to gradually lower that when I do water changes, so we'll see if that raises the pH as well.

Isn't this FUN!?

I have been working to stabilize my ph, here's what I have done. Balance is the key here. First check to see if you Mag levels are up, (because a low mag level will make it hard to maintain both alk +ca) I keep mine up to 1300. Next understand that ph changes throught out the day. (Lowest just before lights come on, and hightest right before lights go out) Knowing this will give you a better idea when to shoot for a target level.
If your house is closed up (A/C) you could have an elevated co2 which drive down your ph. No worrys it can be raised. Its best to use a balanced product (any of the part A&Bs) I use ESV but kent make a good one. Now with the baking soda (which I also use when I run out) I add 2 1/4 per gallon of RO water. Regular BS will not raise the ph, but if you bake it @ 325 degree for 1 hour you end up with baked baking soda or washing soda. Now if you add that, it Will raise the ph (so add slowly).
Victoria