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View Full Version : co2 ph drop vs. buffering capacity



hatton3
01-31-2003, 8:57 AM
Can you expect to see a ph drop if you are injecting co2 and you have a GH of 16 and KH of 5? My TDS meter reads 267 ppm. I just want to know if the water has any co2 dissolved in it if the ph is not becoming acidic because of the resultant carbonic acid from co2.
Do I need to acidify the water to increase the water's co2 carrying ability?
My ph is a rock hard 8.0 right now. Even peat won't move it. I'm afraid to mess with chemicals. Perhaps I am not adding enough co2?

djlen
01-31-2003, 11:10 AM
How are you injecting? Pressurized or DIY? What is your bubble rate?
Len

plantbrain
01-31-2003, 11:23 AM
Get enough CO2 gas into your tank to get the pH to 6.7-6.8 for this KH.
Keep the pH there during the ENTIRE lighting period(all 10-12 hours, not just 3-4 hours in the AM etc).

That's it.
Your tap water is fine.
Don't mess with it.

You might need a better way to dissolve the CO2 and mix it better.
If a fair amount of the Gas bubble escape to the, then work on this part, check the Krib etc for ideas.

Regards,
Tom Barr

hatton3
02-01-2003, 5:50 PM
I'm injecting co2 through 2 Nutrifin Natural Plant systems in a 55 gal. I'm getting a bubble about every 2 seconds (when taking an average of the two systems). By the time that the bubble reaches the top of the diffuser, it is very small (a small pin-dot in comparison to it's size when it started-pea sized). Interesting thing, there are micro bubbles on all of the leaves of my plants that drift upwards - I'm assuming that this is o2? Perhaps my ph test is not accurate- it is a TetraTest.

Oh, I do a 20% water change a week.

220 watts of light via 2 VHO 48" tubes powered by an Ice Cap. I dose Kent Freshwater plant and Black Water expert, but it does not color my water. I have no algae problems but my phospate is about 1.5 mg/L.

I swear, the plants are growing almost overnight. I think that my Java fern grew 1 inch today, and my crypts were very thin looking when I bought them. A week later, they have grown new foliage and are very thick and beautiful.

As far as pressurized co2 - I don't want one around the family. Although I've never seen them shoot off like a torpedo, one of the o2 tanks in the clinic at work fell and bent the regulator. The sound was deafening to say the least. So... I've never trusted them since.

Thanks Len and Tom for all of your help - it is much appreciated!
:) I'm really enjoying the hobby.

plantbrain
02-01-2003, 9:00 PM
You sound like you have enough CO2.
When plants act like this, then things are going right. It surprises folks how well plants grow when they get everything they need.

Your tank will eat all the nutrients in the water so you'll need to keep up on the CO2 changes and dosing of nutrients. The plants are using a good deal more now.
You might get a "stalled tank" later if the nutrients are not added also.

Regards,
Tom Barr

hatton3
02-02-2003, 10:19 PM
I'll definately keep an eye on the co2 and nutrients. I don't want algae problems. I actually started the yeast cultures about a week apart so that they would not both stop at the same time. I've got a small amount of peat in my Fluval, and I dose nutrients weekly as well.

Is it normal to have all of these bubbles? There are thousands of them... It is almost like it is snowing in reverse. The cabomba looks like it has snow on it because of all of the the bubbles.

Again, thanks for the help Tom

plantbrain
02-02-2003, 11:11 PM
Yes, it should look like a soda bottle when things are doing well.

That's one thing that really looks cool I think. Certainly got me hooked.

You will need to test the pH often but not the KH.
If you do the routine for the nutrients I suggest and use the tap with 50% weekly changes, it's unlikely you'll need to test for much else unless you want to for other reasons.

Since you are doing well with the CO2 and got that down well(good idea to stagger the DIY brews), let's get you going on nutrients for this tank.

I'll tell you this: this part is easy and pretty cheap.
You can get everything you need from www.litemanu.com or you can find most of these items at the garden section or hardware stores etc. K2SO4 might be tough to find, KNO3 is not. KH2PO4 is available but folks don't need 50lbs of it:-) litemanu has 1lb amounts that last for a decade or two for about 4-8$. KNO3 is about 4-6$ locally(Grant's or Cooke's brands are the best IMO), K2SO4 is also call Potash of Sulfur, Green All brand is good.
Plantex , CMS etc are dry trace mixes, etc.

More info can be found on the krib at PMDD.
You can call up the water department and ask for the NO3 nitrate/nitrogen levels and PO4, phosphate levels for your tap water. They may send you to the Chemistry lab etc but keep on them till they tell you.

You might not need any KH2PO4 for PO4 additions if the tap water has 1.0ppm or more. Less than this and you'll need to add it 1/2 way through the week. 1.5ppm should drop pretty fast as the week goes along.

So for your tank(55gal) add the following:
After a water change(50%)
Dechlorinator
K2SO4=> 3/4 teaspoon
KNO3=> 1/2 teaspoon
KH2PO4=> 1/16th teaspoon(divide a 1/4 into four parts)
10mls of trace element mix

2-3 days later add the same amount of KNO3, KH2PO4 and Traces.
2-3 days repeat again.

Do 50% weekly water change again and start it over again.
You add nutrients every 2-3 days, or about 2-3x a week.

The 50% weekly water change prevents too much nutrient build from ocurring and the regul;ar addition prevent anything going to zero for long(one day at most)

But you need to know what the tap water has in it first, you might not need NO3 or PO4 if there a lot in there or only need to add it once a week etc near the midweek before the next water change etc.

The above routine will give an extra 9ppm of NO3(within 1ppm of error) with each dose. Plenty of K 20ppm + a week etc, enough PO4 and traces.

Teaspoons are cheap.
The chemicals are cheap. Don't be weird about the names, they may as well be sugar, yeast, water and baking soda. Doesn't matter what you call them, don't be distracted by it. They are cheap and easy to add and will really make a tank go well for many years for very little money with good CO2 and you already have the lighting.

Plants need three things: light, CO2 and nutrients, take care of those and the plants will keep growing very well.
Good plant growth= no/little algae growth

Regards,
Tom Barr

hatton3
02-03-2003, 9:45 AM
Again, thanks Tom. You are right, it looks like a soda bottle in there.
If it is okay with you, I'm going to print out your instructions. I'm very new to plants and I'll need a reference to keep from getting mixed up. You have really given me some great advice and I appreciate you taking the time to help me. I took pictures of the tank last night, so I'll post them when I get them developed and scanned in.

You just add those nutrients in dry form to the water, or do you mix it in a glass first? Won't hurt the fish, right?

You won't believe this, but I enjoy this tank much more than my coral tank. I have had great success with the SW/coral thing for 2 1/2 years, and all of my leathers, shrooms, and clownfishes were beautiful. It was so much of an effort in time and money to do it right, I finally tore it down. I just got tired of keeping up. I think that with your plan, I'll have much less maintenance time and more enjoyment time than I did with the reef. And... It is a heck of a lot cheaper! :D

Thanks again Tom,

John

hatton3
02-03-2003, 10:00 AM
Umm,
You'll have to help me on the chemicals, it has been a long time since I've had chemistry.

K2SO4 - Is that potassium sulfate?
KNO3 - Is that potassium nitrate?
KH2PO4 - Potassium phosphate?

Sorry for the question - I just don't have any chemistry books to reference.

plantbrain
02-03-2003, 1:53 PM
Yes, yes and yes.

Using these, you can add whatever ratio of NPK(the numbers on fertilizer bags) you wish without any NH4, NH3 amonnium/ammonia which is bad news.
K2SO4 is for K
KNO3 is for N
KH2PO4 is for P
The extra K is the best for the tank on each salt if you have to pick and choose a cation, say as opposed to Sodium, Na.
But as long as you are not adding muchg Sodium(Na) say like to add PO4, this will not be an issue, but I would not use sodium nitrate etc.

Regards.,
Tom Barr

djlen
02-03-2003, 3:18 PM
hatton3 You can add the N,P,and K dry, right into your filter. You and get P(KH2PO4) in a liquid form by going to your local drug store and picking up Fleet Enema. It is 100% KH2PO4. And a small bottle will probably last for a long time. And it's cheap too!!
But don't forget to check with your water company to find out what's in your tap water as a reference.
Len

hatton3
02-03-2003, 7:07 PM
Thanks! I'll call them tomorrow.