Building RO water up to correct pH, KH and DH

This thread is as a consequence of the Discuss Buffer thread and the pH - KH & GH - in a Discus / planted Tank thread. I will refer to concepts that have been mentioned there, so the reader might want to refer to those threads as well.

www.tropicalaquarium.co.za/showthread.php?10544-pH-KH-amp-GH-in-a-Discus-planted-aquarium

www.tropicalaquarium.co.za/showthread.php?10456-seachem-discus-buffer

I am building my water up from RO and I am trying to get all parameters correct for slightly acidic water, pH between 5.8 and 6.8 and soft, catering for the needs of plants as well.

So we all know by now that you can not keep fish in pure RO water, because of osmosis of the fish and the possibility of pH crash. A few products was mentioned in the Discus Buffer thread, namely Discus Buffer, Discus Trace and Replenish, all from Seachem. We learned that although Discus Buffer increase TDS, it is actually not contributing to kH or gH. I have now done a test with Replenish and determined that it is contributing to gH only and no kH.

That means that I have build my RO water up to the gH that I targeted, but there is no kH in my water. I confirmed that with a test of my tank water now as well, at 0.16kH. What made me investigating this, is @Peter Leid 's thread kH pH and CO2 in planted tanks. The table give values of kH and pH vs the availability of CO2 for plants. That made me realize that, that is another reason for my poor plant growth.

I therefore have to re-visit how I am building up my RO water. I will listen to your input and do some experimenting over the next few days. I am now playing with the idea to use Replenish, Discus Trace, Discus Buffer and Bicarbonate of Soda, to buffer pH between 5.8 and 6.8, get kH to 4 and gH to 8, with the right amount of trace elements via Trace. I will also need to look at available CO2, as a function of my kH and pH levels.

I am battling a bit to understand how acidic buffers work vs kH, which is in essence an alkaline buffer. It seems to me that you can not employ both. Can someone explain that to me?

 

Hi TomK
I think we are getting closer and closer to "the same page" - thinking wise.
I keep an MS Excel table and input all my values in an attempt to find a pattern I can interpret/understand.
In my first attempts, I was using large amounts of SeaChem Discus Buffer - in line with their suggested dosings per litre.
Getting the pH absolutely correct but ZERO KH and very moderate GH.
Laterly I've adopted for less than half the recommended Discus Buffer and gone BIG on the KH booster from HAGEN's Nutrafin.
So in my repelish water resevoir, I get water ready for waterchanges and achieve 8 pH, 10 GH & 7 KH.
(Water at change time is >5 pH, 5 GH & >1 KH)
NEXT morning after the 30% change, water is @ 6.5 pH, 5 GH & 3 KH - within the next 6 days the water will be back @ >5 pH, 5 GH & >1 KH. Bearing in mind that the CO2 levels are climing all the time into the TOO MUCH ZONE.
So until I understand how God gets the Amazon soft and whatever hardness to whatever it is - I guess I'm in for bi-weekly 30% water changes??

 

totally over complicating things. . .

 

So from the above we can understand why it is said that kH do not necessarily effect pH. That will only be true, when there is no acid present in the water to absorb. We can also deduct from this, that should you have acidic water, ie pH below 7, an increase in kH WILL increase pH, as there IS acidity present in the water. This will keep on happening, until all acid is absorbed, or kH is depleted (as a sponge). All acid is absorbed when you reach 7pH. Therefore you cannot have kH in water with a pH smaller than 7pH. With a target of 5.8pH to 6.8pH, it is therefore impossible to have kH present in your tank. @Dirk Bellstedt, would I be correct in stating this?

That brings me to the next issue.

In my first post I said that I want some kH, as available CO2 is a function of kH and pH. From the quote above, we see that this requirement is for planted tanks only, as fish is not affected by kH. I will therefore have to study the effect of available CO2 at kH and pH values lower than the values in the chart mentioned in Peter Leid's thread. I therefore maybe do not need kH in my water, as I can buffer with Discus Buffer, an acid buffer below 7pH, eliminating the need for kH if one can get away with the available CO2 factor in the absence of kH.

 

Hi Singularity
Break it to me gently bru.
Give me the uncomplicated version ASAP - I am my own worst enemy I know. I like to understand stuff but sometimes the light won't turn ON!!:stupid:

 

haha, eventually someone that understand the way I think!

 

That is because of what I explained above. Not possible to have kH with pH below 7pH. GH can be easily increased with Seachem replenish. This is important for your fish.

Because the kH is eaten up by the acid and then pH start to plummet, as there is no more KH to counter.

Please tell me more about the effect of Discus Buffer. Does it keep between 5.8 and 6.8 as advertised and have you found any side effects?

What happens to CO2 availability at 0KH and pH between 5.8 and 6.8? I suppose it is way to high, but that one can counter it with heavy aeration or water surface action?

 

Wow guys slow down and stop!

You are both heading for disaster here with all these chemical additions and deductions you are making.

Firstly, Peter I dont completely understand your problem? You want "more perfect" water than the water in Cape town, for use in Discus tank? You will struggle... I then read that you have to do weekly water changes-no matter how "perfect" your water turn out to be, water changes are part and parcel of discus keeping.

I support your guys effort completely but have to agree with @Singularity, you are really now overcomplicating things.

Firstly, trying to achieve "Amazon" quality water in your tank is impossible, so forget about it. In any event the Discus you have, unless wild are probably 20 odd generations away from wild, so they will be fine in your water. As for plants- discus water in the amazon has very little plant growth. Tree's, bogwood and decaying leaves are in abundance, try replicate that - impossible!

I have commended @TomK for your effort in understanding this, but I feel this is getting to stage where you overcompkicating things. But each to his own, at least I know you not doing it with fish in that water

Rgds

Marco

 

Thanks for your blessing Marco. I will keep digging till I understand this to my satisfaction.

 

Ok I have no intention of messing around with water parameters but would just like to mention something.

Back in Ermelo there was a guy who bred discus in RO water only.

He added something to the RO unit after all the filters, looked like those silicone stuff you sometimes get in pill containers.
Anyway he said they did not bread unless he added this.

Any body know what it is and what it does?

 

@Vis, it sounds like those mineral attachments that turns a 5 stage into a 7 stage. @Marco talked about it before?

 

mmmm... Discus bread


Damn ninja Edit

 

@Peter Leid
I read that a possible side effect with Discus Buffer is that algae might get out of hand, due to Discus Buffer being phosphate based. This however also depend on your lighting. Any experience of this during your stunt of heavy usage?

I am starting to think that my build up of RO with Replenish and Trace only is sufficient. What I am lacking in KH to make CO2 available I can compensate for with aeration and the dropping pH with water changes. I know it is a pain, but I have the water and the time... hehe In my case it is not every 6 days, but two weeks. OK, I cheat by adding a bit of Bi-carb towards the beginning of the second week, when pH is going a bit low. Another advantage that I have is my pH meter that gives me constant digital readout, so I know exactly what is happening. (and my TDS is real GH)

Another angle? haha

 

Hi TomK and Peter Leid,

Man you guys are really making a mountain out of a molehill again........

Singu and Marco said you were complicating matters and you guys certainly are.

Peter, why you use RO water in the Cape beats me stone dead, it is completely unnecessary. You have either been reading too much European and USA discus literature, or you have been listening to Sam from Sam's Aquarium (who wants your cash....). I have kept and bred discus in the bigger Cape Town area in plain tap water since 1988, so why all this complication.

TomK, remember that I told you a while back to purchase the book called "The Manual of Fish Health" right? Have you been reading the chapter on water conditions? You should read that over and over again and then you will get it. Peter, you should also purchase this book to help you with your water chemistry as I see that both of you have major gaps in your understanding of gH, kH and pH.

Just a general comment is that I would use the products of one supplier for hardening up RO water and not combine products from different suppliers. A supplier will aim for a balance between its different products to add GH and KH. To add bicarb on top of other things for example is going to upset everything once again. Tomk, for the record, bicarb is not good for increasing kH and it adds sodium so your TDS will go up but not your kH. Also, addition of Discus Buffer is for addition to water that has a high carbonate hardness, NOT to reconstituting RO water, so don't even go there. It adds phosphate and if you do not have to add this it is going to be better. If you add this to RO water, you can just as well start off with your tap water because producing RO water and then adding all these concoctions is a total mixup and is not getting you and your fishes anywhere.

What I also want to say is that I will not write a whole epistel on this sort of water chemistry to help everyone every time, it will just take too much of my time and every aquarist should buy a good book to understand this stuff. STOP downloading rubbish from the internet and getting yourself confused. There is so much nonsense on the internet from people that do not have the qualifications to understand this that this is a major source of confusion.

Kind regards,

Dirk

 

@Singularity

I'm going off topic here a little bit... but I'm hoping you can help here.

I recall a few months ago when you rejoined TASA you showed us some pictures of the really amazing set up you had prepared. If I recall correctly, you were preparing yourself for Discus imports. I can only assume that you put a lot of money into the set up, but more importantly, a huge amount of studying must have gone into it.
Would you care to share the outcome of your hard work, and how this project is currently going? I'm sure you have some amazing set ups going, with good water quality. You've posted some really nice pictures of your Discus on other threads. I'm sure your comments based on your experience could share a wealth of information on threads like this?

 

Dont have any tanks at the moment, moving around to much, but will be moving to pta in the net week or two. I am saving for a new tank once sttled there but at the current rate it will take 6 years to save up enough, it will be of salty variety though and the house will be built around it.

I am lucky enoygh to have a gf busy with her phd in pharmaceutical chemistry and a friend busy with her phd in "farmaseutika" (she also loves her discus) so we had access to some lab grade equipment over the weekends, anyway, we tested RO and tap mixes and found a 2 to 1 RO tap mix was the best we could get interms of gh kh and stability (this is in potchefstroom, everyone that has very hard water out of tap should do some tests to see what their best ratio will be). So i actually just kept with this "recipe" for the fishroom tanks, i used the test strips and a tds meter on every mix i made to make sure everything was in the ballpark, just a rough and quick check. Fresh mix had a ph of 8.2-8.4 usually and stabilized at 7.5 after 2 or 3 days of aging. This is what i found while preparing water in the early stages when i was worried about the correct ph and so on. Once you see fish do very well in higher ph water you kind of put it on the back seat, i never tried to breed any fish so i had no need to alter the ph for any reason, my soul objective was to get discus thriving, and they did.

In the end, i guess, you have to find something that works for you, and once you find it not mess around with it, just do it religiously. If its not broken dont fix it.

 

@Peter Leid, looks like because you dared joining me in the discussion, you are now on the hit list as well.

Dirk, if you followed the links I gave as background, you may have noticed that Peter is not using RO.

 

Hi Tom and Peter,

What I am indicating to you is that you don't need most of this stuff and that I can save you a lot of money in this way. If you don't want to do this, then it is your decision.

Kind regards,

Dirk

 

Hi TomK
I know what you mean bru.
But when you've been around the block a few times like we have - you can take a little stick without resorting to nappies :laugh:.
I only joined the forum three days ago because my Buddy Trevor Pleco said it would be interesting..... he got that right!
@Prof Bellstedt
I'm new to this TASA forum stuff but I'm not new to fish keeping.
I don't understand stuff like the relationship between pH and frikkin KH & GH - but I'll get there.
I'm moving away from a scenario where what happens...... happens - towards why it happens.
Your advice is appreciated and acted upon Prof.

 

Hi TomK
Got a little side tracked - but back to your question:

@Peter Leid
I read that a possible side effect with Discus Buffer is that algae might get out of hand, due to Discus Buffer being phosphate based. This however also depend on your lighting. Any experience of this during your stunt of heavy usage?I have never experienced algal growth in my community tank.
I suspect aggressive lighting will be more of algae stimulator than any phosphate from the Discus Buffer.
I had an algae problem in my plant aquarium when my lights were too much - changed the lights (Thanks Trevor Pleco) and the algae went away - and the Discus Buffer remained.......:ciao:
The SeaChem Discus Buffer does exactly what the label says it will - and the KH goes down and stays down too:sad2:
The GH appears unaltered