RO Right ?

Was wondering what products others use for their RO water ?
My tap water only has a TDS of eighteen, which is fine for breeding soft water fish but i get very slow growth rates due to the lack of anything in the water for the fish to form bone structures with.
Have been using a powdered RO right but have found it doesn't dissolve 100 percent and leaves traces on the bottom of the tanks



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Buffering very soft water

Hi all,
Ken it is an interesting question, but I've had a couple of thoughts, bone is mainly calcium phosphate, and one thought was that I'm not entirely sure you have to add anything to your tap water, I think if you feed a varied diet this should supply all the nutritional requirements of the fish, for example I'm pretty sure that commercial flake/pellets would supply all the nitrogen and phosphorus you need.

Calcium would be supplied when you make sure the water has enough carbonate buffering (to stabilise the pH), you could buffer it up with the traditional coral gravel in your filter, or with any type of mollusc shells (snails, mussels shells, oyster shell "chick" grit etc.,) the biological aragonite form of calcium carbonate is more soluble than calcite from limestone etc.
You only need to go to 2 or 3 degrees Kh.

If you did want to add some other minerals, some are easily available over the shop counter, "Epsom salts" are magnesium sulphate, "bicarbonate of soda", sodium carbonate and "sodium free salt" is potassium chloride, that should do for the most important nutrients, I haven't worried about iron as this is much more soluble in soft water, so that shouldn't be a problem.

A last thought would be that some bottled waters are very mineral rich, so it may be you could just add a bottle of "Peckham spring" or similar when you change your water.

There is an analysis of some bottled waters here:
<http://www.fsmq.org/data//files/fmsasminersi-3742.doc>

From the list, "Badoit" is incredibly mineral rich (which you want) but also has 1ppm fluoride (I don't know whether this is fish safe), but I'd probably avoid this one), I've never tried it, but it must taste absolutely disgusting. In contrast "Volvic" is very low mineral, and probably fairly similar to what you get out of your tap. (Also "Cumbrian" has a whopping 31ppm nitrate, worse than the majority of UK tap (50 ppm is the legal limit for tap water)).

My choice would be "Abbey Wells", some calcium and magnesium and not much nitrate or fluoride, "Ballygowan" or "Ada Spring" would also do.

cheers Darrel

I wouldn't add bi-carbonate of soda to get a higher kh to help the fish, as it pushes the ph of soft water up too easily.
My tanks have minimum buffering, and anytime i tried bi-carbonate to get a kh of 2 to 3, it pushed my ph up to 7.8.

I use whole oyster shells (another person recommonded them), one shell per square foot of tank, they do not affect tank chemistry much as they are very slow dissolving, and will not buffer a heavily stocked tank, but they will release trace elements as they slowly dissolve.
The oyster shells and regular water changes are best for fry raised in really soft water, IMO !

Hi all,
Andrew's is a good point, the softer the water is the less buffering it has, Ken's water has virtually no buffering, so pH is a fairly meaningless measurement, which will fluctuate wildly up and down with any addition of a base (bi-carbonate of soda for example) or acid (even CO2 dissolved to form carbonic acid).

Even more important he also has personal experience of this problem, where I understand the principles, but I have water that comes out of the tap as virtually infinitely buffered "Lake Malawi", and even our rainwater is more base rich than Ken's tap supply.

A 10g oyster shell, being aragonite will carry on leaching calcium carbonate into the water, but at a much slower rate than the the chemicals, but also at a slower rate than say 10g of oyster shell chick grit, which would have a much larger surface area exposed to the "solvent" (in this case slightly acid water).

cheers Darrel

Thanks for that.
Forgot to say i use Kent PH stable which is a kind of 'KH plus' powder.
Used to have bags of crushed oyster shells in my Koi pool which worked ok, but was thinking this might not be able to cope with large water changes in breeding tanks ?( Hardness would drop to zero then build again slowly, might be a good thing for spawning ?!)

.

Darrell, i agree with what you have been saying, apart from adjusting the kh, it's just that i've found trying to get some decent buffering in soft water a real pain and not worth the hassle in the end.

And sorry, i should have said using any type of kh booster pushes the ph of my soft tap water up too easily, not just bi-carbonate of soda.

When i was trying to get some buffering in my tank water, i found to have a kh of 2 my ph went up at 7.6 and to get a kh of 3, my ph went up to 7.8.

When i used ro water and reconstituted it with RO Right, it didn't affect the water parameters of; ph 6.7, kh 0 & gh 0, it only increased the tds.
Then when i added a teaspoon of Kent's kh plus (can't find it for sale anymore) to add some buffering back into the water, it pushed the ph of the ro water up to 7.2 and that gave me a kh of 1, and the more i added to get more buffering the higher the ph went up.

So i decided in the end, to just use an hma filter and stick with my water as it was; ph 7.2, kh 1 & gh 1, it is ideal for breeding, even though it is loaded with phosphates, the deepest blue on the scale when i check it, and only one person has said to me high phosphates are detrimental to a fishes health over time, and i suppose i am going to find out about this over time.

If you do not stock too your tanks too heavily, put something like oyster shells, crushed oyster shells, etc, in your tanks, and do small daily water changes to help replenish the minimal kh you have, you will be fine.
With fry tanks that are well stocked, and get heavier feeding, plus there will be more waste produced, i just increase their their daily water changes to 50%.
And all my adult and fry tanks have been fine.

Because i did notice, if i concentrated on my plec tanks each day and only gave my cory tanks a weekly water change, the ph in their tanks dropped over a week, and i lost a few panda corys before i realised what was going on !

Hi all,
Andrew, sounds a sensible approach, and it would be my suggestion for "Highland Ken". Andrew wrote: "If you do not stock too your tanks too heavily, put something like oyster shells, crushed oyster shells, etc, in your tanks, and do small daily water changes to help replenish the minimal kh you have, you will be fine. With fry tanks that are well stocked, and get heavier feeding, plus there will be more waste produced, i just increase their their daily water changes to 50%."

If you did want to raise the pH in the water change water you could decant it in to a container with oyster shell in it for 24hours, finer the shell fragments the more rapidly the the calcium carbonate will dissolve.

The phosphate problem sounds familiar too, in fact back to the "plumbosolvency" thread, "the phosphate is from the compound the water company add to the water to keep it above pH7 & stop it leaching the lead from the water pipes." More on this here:
<http://www.plecoplanet.com/forum/showthread.php?p=10638>.

From Andrew's description of what happened I reckon that the "R.O. right" only contains a small amount of calcium and/or magnesium carbonate (it's only the 2+ ions that contribute to "hardness"), may well be that the magnesium content is magnesium sulphate etc.. (I'd be quite interested in the actual chemical composition of all of these buffers, as I think £12 for 250g of "Kent's R.O. right" might be a bit of a mark up (in fact I would imagine several hundred percent over the cost of the chemicals)).

The "kH plus" presumably only contained carbonates, because your water is low TDS, any small addition of it will cause a dramatic rise in pH.

pH itself is a bit of a funny measurement "The pH scale is not an absolute scale; it is relative to a set of standard solutions", because it is logarithmic scale in this case pH8 is actually 10 times more alkaline than pH7, so each addition of carbonate will add a lot more carnbonate buffering (the potential to neutralise an acid), but will only change the pH by a small amount.

cheers Darrel

Darrell
It was Kent PH Stable (powder form) i used, it only says on the tub; "Contains carbonic acids and monosodium salts" ?

At the end of this link it tells you some ingredients; Hosue Hold Products Database

Thats the stuff i use (PH stable) as well as RO right. Doesn't alter my PH at all, stays at 6.8.?
I take TDS up to around 90 and that gives me trace readings of GH and KH.
Fish seem happy, breed ok, just slow growth rates.

.

Hi all,
Brilliant link Andrew, I've book-marked the "Kent Marine inc" page and I'll go through all the products when I've got time.

As I suspected it would be fair to say that Kent are not being totally honest about what there product contains, and as for the price they are definitely taking the p*ss. The "Contains carbonic acids and monosodium salts", is sailing pretty close to being an "untruth" and definitely designed to suggest to the chemically savvy that this is a complex compound buffer, rather than a small amount of very cheap borax, and a lot of cheap filler.

"Kent pH Stable"
Chemical Percent
Sodium bicarbonate <90
Sodium carbonate <20
Magnesium carbonate <5
Sodium borate decahydrate (borax) <5

So basically you are buying sodium bicarbonate ("bi-carbonate of soda"), and sodium carbonate ("washing soda"), both will increase the GH and pH, but not the KH (they will disassociate to Na+ ions).

The small amount of magnesium bicarbonate will increase the KH marginally (Mg2+ ions), but it is really in there as the "anti-caking" agent, they add it to table salt "Because of its water-insoluble, hygroscopic properties MgCO3 was first added to salt in 1911 to make the salt flow more freely." It is also the ingredient of heart-burn tablets "milk of magnesia".

The contains carbonic acid bit is very misleading (and belongs here) it comes from this "magnesium carbonate can also be synthesized by exposing a magnesium hydroxide slurry to carbon dioxide under pressure (3.5 to 5 atm) below 50 °C, which gives soluble magnesium bicarbonate":

The "borax" (sodium tetraborate decahydrate) is actually the pH buffer, it is a very alkaline buffer and would buffer the water up to about pH8 or higher if there was more of it. The "decahydrate" bit just means the salt contains a lot of water (Na2B4O7·10H2O), it's the 10H2O.

cheers Darrel