vinegar dosing at 15ml/90g should it be changing?

[metalManiac]

hi guys, i have a phosphate issue that i have been trying to resolve (1st step was to sell all my tubastreas and reduce feeding )

i have been feeding quite lightly now and phosphate is staying around 1.5ppm! with nitrates at around 35ppm.

I have been dosing sugar initially (as per the "Vodka Dosing...Distilled" reefkeeping issue but substituting vodka for sugar/vinegar) (sugar is doesed in granulated form) and have worked it up to 3tsp! a night (worked up over 1.5 moths with small gradual daily increases until i see a drop in phosphates/nitrates). The skimmer was working overtime pulling out plenty of skimmate but the phosphates/ nitrates never dropped. (i have a octopus nw-200 meshmodded on a 90gal).

According to other people experiences, the nitrates/phosphates should be dropping by now. So, determined to make it happen (but not crash the tank), i have decided to abandon the sugar and try for vinegar dosing.

Well, bit by bit, and i am up to dosing as much as 15ml per night without any significant drops in phosphate or nitrate and the skimmer is not producing anywhere near as much skimmate as it did with the sugar.

I have not experienced the 'snowstorm' effect, no bacterial slime blooms and no decrease in PO4 or NO3 at any time.

other parameters are:
Ca = 440ppm
Alk = 12dkh
pH = 8.22
sg = 1.027
and of course...
NO3 = 35ppm
PO4 = 1.5ppm
temp = 26 degrees celsius

running a shallow sand bed (no dsb or refugium <- both not an option atm as the skimmer has taken up all the room in sump).

The only thing i can think of is the LR is leaching phosphates at a ridiculous rate, otherwise im just stuck.

anyone have any advice? (did i overlook something?)

[HighlandReefer]

I add vinegar to my top-off with kalk. You will get a dual benefit using it this way (an increase in calcium). The recommend starting point would be 15 ml vinegar/ 1 teaspoon kalk / 1 gallon of rodi. Depending on your consumption of alk., it would not be unusual to dose 30 ml. vinegar/ 2 tsps. kalk/ 1 gallon rodi. Assuming your 90 g. tank evaporates around .75 g - 1.0 gal. per day, then you could easily increase the vinegar dose slowly, watching for excess bacterial growth. I am dosing vinegar at a higher rate, because I need at least 45 ml. vinegar/ 3 tsps kalk/ 1 gallon rodi to keep up with consumption. In my situation, I was able to get the nitrates & phosphates down very low using vinegar, but still needed to resort to other means to get them down low enough to stop the microalgae growth. I added a DSB with chaeto and installed a GFO reactor. I do have a lot of fish and feed them well.

Limits To Limewater...Revisited
http://web.archive.org/web/20030618...bio/default.asp

Expanding the Limits of Limewater: Adding Organic Carbon Sources (vinegar)
http://web.archive.org/web/20030418...bio/default.asp

Phosphate and the Reef Aquarium
http://reefkeeping.com/issues/2006-09/rhf/index.php

Nitrate in the Reef Aquarium
http://www.advancedaquarist.com/iss...st2003/chem.htm

[metalManiac]

thanks Cliff, i guess 15mL is not as much as i would have thought...

im not dosing kalk atm as nothing is growing (the phosphates are inhibiting growth). so atm its simply pure vinegar being dosed, i will change to a kalk mix later on.

[HighlandReefer]

One of the primary concerns when dosing a carbon source is when the source is added, oxygen levels may decrease to much lower levels, particularly at night. I would recommend that you split your doses over the course of the day, or even better, use a dosing pump.

[metalManiac]

will do. ill update this page with results.

thanks Cliff!

[HighlandReefer]

Your welcome.

[metalManiac]

well, i said i would update with results so here i am.. even if it has been a few months!

Ok, to bactrack (because this information might help people).
i was getting nowhere with the vinegar or the sugar, the phosphates/nitrates remained the same and corraline/corals were not growing so phosphates were not being bound either.

Frustrated, in January i gave up on dosing sugar/ vinegar and let the tank "do its thing" until the start of Feb. (i was sporadically away during January so that was another reason for suspending dosing).

I began to wonder about monocultures in my tank (as the LR is roughly 6-7 years old) as well as the theory behind vodka dosing and had decided to do a last dosing regiment of 80proof vodka (with some alterations) before i go buying new LR and rearranging everything.

I started the dosing of Vodka , increasing the dosage by 1mL every 3 days. Finally I am currently sitting on 10mL dosing and my NO3 is at 5ppm and PO4 is at .5ppm, so im happy to ride this out at the moment and see where it leads me to.

IMO these were the contributing factors to my previous failures (let me know what you think guys).

1. It was a case of 'too much too soon' with sugar, i had overstepped the optimum dosing amount. This meant that the bacteria grew and used the nitrate/phosphate, but since the skimmer could not keep up with growth, the bacteria most likley died and released the contaminants back in the water.

2. Vinegar dosing did squat, i believe because i abandoned the project too early thinking i overshot the optimum point (but vinegar being quite weak i was actually not dosing enough).

3. (MOST IMPORTANT) i did NOT regularly clean my skimmer cup (sometimes a week at a time). The whole idea behind vodka dosing is to strip the water column of bacterial growth before it dies off and recontaminates the water. I most likely had growth, but the nutrients were not being exported via the skimmer. I now religiously clean my skimmer every 2nd day (i have noticed that at this point the neck is filled with junk and waste production begins to drop off).

Hopefully people can learn from my mistakes when it comes to dosing vodka.

[metalManiac]

BTW, i still have not experienced ANY snowstorm or bacterial bloom effect.

and, corraline has begun growing as well as corals so im guessing that in addition to phosphate being exported via the skimmer, it is being bound as well through biological processes.

[Randy Holmes-Farley]

Glad to hear things are turning around!

[HighlandReefer]

Originally posted by metalManiac
Finally I am currently sitting on 10mL dosing and my NO3 is at 5ppm and PO4 is at .5ppm, so im happy to ride this out at the moment and see where it leads me to.

Great to hear that you were able to reduce your levels down so dramatically in 3 1/2 months. If my calculations are correct, then you were able to drop nitrates about 0.3 ppm per day. Nitrates dropped from 35 ppm to 5 ppm.

One of the problems with monitoring the drop in phosphates and nitrates is that at higher levels, test kits do not detect the small weekly changes from your dosing (possibly monthly changes too). At this rate, you should be down to 0.2 ppm nitrates in about 16 more days. At that point, IMHO, you will need to cut back on the amount you are dosing or risk possible problems (bacterial blooms or too low nitrate levels). It will be interesting to see how low your phosphate levels drop.

Are you running GFO?

[metalManiac]

nothing has changed Cliff, not running GFO. I have not even completed a water change the whole time (i wanted to prove the process to myself, not simply begin diluting) so the whole process is basically due to dosing.

[metalManiac]

definitley agree about the dosing and test kits, it felt like the drop in NO3 was exponential, but, as you stated, its more the test kit readings.

Should i try and back off on dosing to 9mL to try and determine a dose which would plateau out the PO4 and NO3 drop?

[Genetics]

Originally posted by metalManiac
IMO these were the contributing factors to my previous failures (let me know what you think guys).

1. It was a case of 'too much too soon' with sugar, i had overstepped the optimum dosing amount. This meant that the bacteria grew and used the nitrate/phosphate, but since the skimmer could not keep up with growth, the bacteria most likley died and released the contaminants back in the water.

2. Vinegar dosing did squat, i believe because i abandoned the project too early thinking i overshot the optimum point (but vinegar being quite weak i was actually not dosing enough).

3. (MOST IMPORTANT) i did NOT regularly clean my skimmer cup (sometimes a week at a time). The whole idea behind vodka dosing is to strip the water column of bacterial growth before it dies off and recontaminates the water. I most likely had growth, but the nutrients were not being exported via the skimmer. I now religiously clean my skimmer every 2nd day (i have noticed that at this point the neck is filled with junk and waste production begins to drop off).

Hopefully people can learn from my mistakes when it comes to dosing vodka.

1. The sugar sounds like it was working for you. Even though this method works, I do not like the amount of sugar being added to a reef tank in high amounts. If you would have stayed at 3tsp my guess would be that you could have also acheived similar levels to that of vodka.

2. Vinegar usually is sold at 5% concentration. So with 15mL additions you were much lower to the additions of sugar or vodka.

3. I'm a big proponent of vodka. If you are still pulling out dark skimmate then it will eventually drop.

[HighlandReefer]

Originally posted by metalManiac
definitley agree about the dosing and test kits, it felt like the drop in NO3 was exponential, but, as you stated, its more the test kit readings.

Should i try and back off on dosing to 9mL to try and determine a dose which would plateau out the PO4 and NO3 drop?

It may be easier if you let your nitrate drop to about 2.5, where you can see the changes a little easier with test kits. If you wait til zero, then you will not be able to see increases & decreases.
I guess it depends on which test kit you are using. I find that if I let my nitrate drop below 0.2, it has a negative effect on my soft corals. The SPS corals seem to like it below 0.2.

[metalManiac]

will do Cliff,
thanks for all the advice everyone!

ill keep this post updated.

[metalManiac]

update:

the NO3 and PO4 both dropped to 2.5ppm one and a half weeks ago. I the decided to begin feeding the tank twice as much as previously, my fish were suffering somewhat from reduced feeding in my zeal to stomp out phosphates and nitrates.

Dosing still remaines the same; todays result is, NO3 is 2.5ppm, PO4 is 0.5ppm.

atm im just playing with feeding amounts to strike a balance with the current dosing amount.

I have not done much reading in NO3/PO4 uptake ratios due to vodka dosing, does anyone have any info or quick reads? (my results indicate that the ratio is not 1:1, either that or my fish food is laden with phosphates).

[HighlandReefer]

I believe that Randy has made statements to the effect that foods can contain quite a bit of phosphate. I have found that reducing my fish feeding to once every 3 days has helped quite a bit and my fish are still happy. Doing something like this may be dependent on the types of fish you have. I find that I can feed more to make sure all my fish get fed and still maintain phosphate and nitrate levels with less dosing of carbon sources.