RO reconstitution plan ? - The Planted Tank Forum
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post #1 of 6 (permalink) Old 01-13-2006, 06:10 PM Thread Starter
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RO reconstitution plan ?

Could someone give me a quick review and sanity check on my game plan to reconstitute my RO water, please. I just used the last of my RO Right and luckily received my Greg Watson order. I’m going to attempt the dry fertilizer route. The searches on this which I did find all mentioned using either Kent’s RO Right or Seachem’s Equilibrium and if I understand the chemistry correctly I should be able to reconstitute fully from Greg’s products for a lot less $$. Here’s what I have:

1 lb-CSM+B
1 lb- KN03
1 lb-K2SO4
1 lb-MgSO4
1 lb-KH2SO4
1 lb-CACL2
1 lb-CACO3

This is for my 135 gal (see signature) which just last weekend I set up and did the initial “light” planting. I have a couple of pictures and am going to start a journal in the photo album soon as I can start hosting the images. I’m planning on doing 40gal (~30%) weekly water changes from 100% RO water mixed below. I am that small % that have to use RO. Most of this info was compiled from Chucks Calc., Rex’s site, and many many postings.

To 40 gallons mix:

Qty..................Provides ppm..........Target ppm
2 tsp MgSO4......7.08 ppm......Mg......5-10ppm
½ tsp KNO3.......11.57ppm...Nitrat..... 0-20ppm
........... also....... 7.18ppm.....K........10-20ppm
½ tsp K2SO4........ 8.33ppm.....K........10-20ppm
.25gr KH2P04........1.16ppm....P04......1-2ppm
¼ tsp CSM+B.......(.1ppm).....Fe........(.1-.2ppm) (plus additional trace’s)

I found a thread mentioning 1/16 tsp of CSM would increase Fe in 10gal by .1ppm so I multiplied it up to 40gal for my situation and Fe seems to be the popular trace mineral for tracking and measuring reference.

This will eventually host adult Discus so I plan on keeping the GH and KH both at 5dh (kind of soft). I’ll mix this concoction up and will test the KH and GH and add the appropriate amounts of NAHCO3, CACL2, or CACO3 to bring them both up to 5. I wouldn’t expect it to take to much NAHCO3 with the mg ions already present, maybe a little more carbonate however. Chemistry wasn’t my strong point so I can’t figure out the moles, weights and ratios to mathematically work this out beforehand so I’ll resort to the old fashion keep adding a little more and testing till I hit the mark methodology…lol From all I’ve read on reconstituting water, macro and micro nutrient requirements, this should work and provide my baseline for water change day in my dosing schedule.

Do you see any glaring holes here, I hope I'm pretty much on track? TIA

BTW – The algae has started sprouting all over and I believe I don’t have enough “fast growing stem plants” to out compete. I stumbled across a few threads discussing the initial cycling and new tank syndromes and just realized I don’t have nearly enough plants to start out with…I guess off to the store tomorrow Oh, I also have a gram scale on order and will convert all tsp. reference to grams when it arrives.

Thanks Don
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post #2 of 6 (permalink) Old 02-06-2006, 12:57 PM Thread Starter
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Nobody hmmmm?? I'll try to keep this one shorter..

The 40gal tank didn't materalize and I'm actually using a 33gal Rubbermaid Brute. Here's what I've discovered thru trial and error testing.


7 gr. CaCl2
3 gr. KNO3
.1 gr. KH2PO4
5.5 gr. MgSO4
15 gr. Baking Soda
.2 gr. CSM B+

Gives me (measured):

NO3 = >12.5 -<25 ppm
PO4 = 1 ppm
GH = 4.5 deg
KH = 4.5 deg
Ca = 25 ppm

I had to increase the planned CaCl2 and MgS04 quantity (keeping with a ~4:3 ratio) to get the GH up to where I wanted it, although still within the upper Fertilator targets.

What really concerns me is the 15 gr. of Baking Soda to get the KH up to 4.5 deg. Seems like a lot for 33 gal. of water but this is what it tested out too. Does this sound right? My methodology was to add a little more circulate for 2 days and measure, repeating till it measured to 4.5.

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post #3 of 6 (permalink) Old 02-06-2006, 03:09 PM
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Originally Posted by Don135
What really concerns me is the 15 gr. of Baking Soda to get the KH up to 4.5 deg. Seems like a lot for 33 gal. of water but this is what it tested out too. Does this sound right? My methodology was to add a little more circulate for 2 days and measure, repeating till it measured to 4.5.

sounds about right. i used to add 1/2 tsp to 8 gals to get 4dKH
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post #4 of 6 (permalink) Old 02-08-2006, 06:21 AM
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maybe you add too much phosphate and nitrate - and that's why algae started to grow?
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post #5 of 6 (permalink) Old 02-12-2006, 12:01 AM
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You might want to read Wasserpest's new corner tank thread in the Photo section. He goes real easy dosing ferts at first to see deficiencies and trys adding a little bit at a time. With a new new tank, too little is way better than too much. I would try to get some help from one of the experts, preferably one who uses RO water. Some of the mods do I believe. Also, I recently found out that if you add calcium chloride and epsom salts (mg) at the same time, a natural outcome is a precipitate that becomes harder to dissolve called calcium sulfate. So, for my near RO water (well water with zero GH/KH) I am starting to add the calcium chloride first, then half a day later add the epsom salts. Thats just for the GH. For the KH I use baking soda too. And I have crushed coral in the cannister filter to replenish lost KH due to the injected CO2.

Here is a gram formula for calcium and Mg:

To raise a 50 gallon tank to 4 dGH with a 4:1 ca:mg ratio, add 15.88 grams CaCl2 and 6.66 grams MgSO4.
Or an alternate ratio:
18.6 grams of cal. chloride and 10.4 grams of Epsom salts to raise GH up 5dGH in 50 gallons of water 3:1 ratio Ca/Mg

Also, I add about 1.5 teaspoons of potassium sulphate to my 50 gallon change water. Finally, you might have better luck posting this in the general section to get faster feedback, although this is technically the right place to post such questions. Good luck. bob

Three Tanks...Eheim 2128 & XP3-90G, Eheim 2128-65G, Eheim 2232-25G.... Tek 4x54 watt T5-90G, Aqualight 96watt PC 65G low tech, 65 watt Aqualight-25G.... Hydors-90G & 65G ... Flourite in 90, 65, & 25 Gallons, .... Auto Water Change/Auto dosing on 90 & 65 gallon..... AGA member......
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post #6 of 6 (permalink) Old 02-18-2006, 01:46 PM Thread Starter
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Thanks for your inputs. I've discovered two errors based on it. One in my formula - I some how neglected to add the K2S04 back in my formula when I converted everything over to grams. I just plain left it off and didn't catch it until I read your replies. And my understanding of the correct Ca/Mg ratio was 4:3. I did read that somewhere, but upon checking the source found in context it was a high reference and 4:1 or 4:2 works for most aquariums.

I've been doing 30% weekly water changes for 6 weeks now with the wrong forumula (reduced K). Oh and one more FUBAR, I also found out I've been underdosing nitrates and phosphates. They bottomed out a couple weeks ago but I wasn't sure of my test kits accuracy until I recalibrated and validated them (NO3, PO4) with known solution mixes (again). They were still reading accurately so I have to increase my dosing. The plant mass has nearly doubled (excluding the algae) and I guess they're really consuming the nutrients.

I don't need a rocket scientist to tell me know why my algae is running rampant...Just a big enough club to hit me on the side of the head.

On a good note the GH, KH, is holding steady at 4.5 and CO2 is between 17-27ppm (pH 6.7 Am to 6.9 PM) Maybe a little high on the Mg ratio but I have bigger problems than that.. I did a dry dose last night making up for the NO3, PO4, and K deficiency and will be doing a WC today with the CORRECT formula.

I'm off to find a gallon of peroxide to pull a lot of my plants for a "dip" and several spot treatments in the tank on some large pieces of driftwood which I dont really want to remove (major PITA). You wouldn't believe the staghorn I have right now...
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