Waste vs. dosed

[fish_4_all]

I have high levels of both NO3 and PO4 in both of my planted tanks.
Tank 1 always has 20-30ppm NO3 and 2-4ppm PO4
Tank 2 always has 30-40ppm NO3 and 3-4ppm PO4
Dose 1/4tsp K2SO45 every other day and MgSO4 1/8-1/16 now for lower GH, CSM+B at .2ppm iron
Lighting is 80 watts divided over both tanks
All other parameters are normal
CO2 at 19 ppm in both tanks. I know I need more but I need advice on how to do it without pressurized.
Neither tank needs to be dosed with NO3 or PO4 very often if at all. Feeding is actually very low as my fish always eat as much as I feed them in less than 5 minutes and I feed once a day.
Tank 1 - 11 cories, most under 1/2 inch, and 2 BN
tank 2 - swords galore, 3 adults and mostly very small fry and 3 corys

The problem is, I have green spot algae all the time and my levels are that all the time. Do I need to dose some NO3 and PO4 in order to get rid of the algae or are the natural waste levels enough for the plants to outcompete the algae for food?

Does anyone have any experience with dosed levels being more effective than natural levels?

 

[Purrbox]

Based on the information in your "myinfo" I'm guessing that the two tanks in question are 10 gallons. It sounds like all of your parameters are balanced if a bit high. The only thing that seems out of line is the CO2.

To improved you CO2 levels you will need to either add additional CO2 generator bottles, switch to a more efficient method of diffusing your CO2, or both. Some additional details about your CO2 setup would help us to give you some more specific suggestions on what to try.

 

[fish_4_all]

Simple passive setup, 3 liter bottle into a "bell" I made out of a little plastic organizer. A picture is in my gallery of the CO2 setup. The bell is always full and when running at full production, it produces enough CO2 that large bubbles bubble out about every half hour or so. More than enough production, just not a ton of absorption I guess. Side of the bell is right next to the intake from my AC for circulation.

I know I need to make a better diffuser, probably the one with the powerhead and tube because there is little chance of my affording pressurized anytime soon.

At least the algae is growing a ton slower than when I didn't hace CO2. Before I added it the algae was enough to feed my BN and never give them anything extra. Now I have to suppliment their diet.

Can anyone suggest the right powerhead to get because my LFS only has the ones with the large opening in them. Is there also a good place to get the suction tubes for the setup or can I use any clear tube?

 

[czcz]

Are you trimming and removing dead plant matter before it breaks down in the tank? Not overfeeding?

Anecdotal evidence says high organics from high bioload can lead to algae problems. With such high NO3 and PO4, and assuming you've tested the test kits, I think your best course of action is to increase water changes and plant mass, then dose as necessary.

There is some thought that inorganic NO3 and PO4 (from KNO3, KH2PO4, etc) is more important to plants than organic NO3 and PO4 (fish food, waste). Over my head, but perhaps you do need to dose N and P. If you do this you should adopt a resetting system with many water changes over the week, though.

 

[newfound77951]

Hmmm....I just had a thought prompted by czcz's comment......the test kits that we use to test N and P only test inorganic N and P....not the organic forms (I test nutrients for work which is how I know). Testing for organic N and P is a very different process. czcz is right that most plants preferentially use inorganic N and P over the organic versions. Your fish and plants do give off organic matter, but the bacteria in your filter and elsewhere convert the dissolved organics into the simpler inorganic forms. Assuming that you have a properly cycled filter, and a reasonable bioload, the fraction of organic N and P should be fairly small. If you see lots of bubbles at the tank surface, or a surface film, that can be an indicator of high organics. If you think that you do have an overload of dissolved organic material, filter carbon will remove it (along with some of the inorganics but not as efficiently).

So what your test kits are showing you is the levels of inorganic N and P in your tank only, not the organic N and P. With that said, I don't think you need to dose either one, since the ferts that most of us use are also the inorganic forms. czcz's suggestion of more water changes and more plant biomass, and Purrbox's suggestion of increased CO2 sound on the right track to me.

I also run my tank on a tight budget (starving graduate student). I use the Red Sea turbo CO2 setup on my 55, and I think the active diffuser works pretty well. I have 2, 1 liter CO2 bottles hooked up to one diffuser, and also supplement with Excel a couple times a week, and (currently) have very little algae in a high light (192w) 55 gal. The Red Sea system is about $20 online.

 

[czcz]

newfound77951, lets say someone adds 10ppm of organic NO3 into a typical, cycled tank with a healthy biofilter. What is the amount of time (ballpark figure) before it is converted to inorganic NO3? Will the result be 10ppm inorganic NO3, or is it not a 1:1 ratio?

When we cycle a tank and test NH3/4 and then NO3, are we really waiting for organic ammonia to convert to inorganic ammonia, then organic to inorganic nitrIte, then organic to inorganic nitrAte? Or is the organic-inorganic thing only because nitrates are the last step of the biofilter?

Thank you.

 

[fish_4_all]

Wow, lots of good information, I like this. I do have a well astablished tank and the plant mass isn't that high although i am working on that.

I don't overfeed, I don't think so anyway. No waste food in the tank that I can ever find. Large fish population and big waste producers, corys, swords and BN. 50% water change very week.

Test kits tested by my and verified by LFS.

$20 I can handle if it is going to make a big enough difference. What kind of CO2 levels do you have newfound?

 

[7Enigma]

I would slightly decrease your phosphates (closer to 1-2ppm) and as mentioned increase your CO2 diffusion. If these are indeed 10gallon tanks you should be able to EASILY get over 30ppm if you wanted to on a 2L (per tank) setup. Since you have an AquaClear HOB filter I would recommend plumbing directly into the filter. I had previously used a passive system similar to yours, and while better than most passive systems it still could not compare to injecting directly into the HOB.

What I did was to cut one of the plastic "pleats" off of the intake tube of the AquaClear, which is the perfect size to fit the CO2 air tube. I then placed the tube about 1" up the intake (so no CO2 bubbles outside of the intake and miss the impeller).

Also make sure to keep your water level as high as possible so there is little "waterfall" effect. This will keep the highest amount of CO2 in the water as possible. Every other day or so I normally pour a large glass of tap water into the tank to make sure the level stays high (I also dose my potassium at this time and so do not use any dechlor, and its only about a cup or 2).

Let me know if you need pics, I'm about due to clean out the intake (it gets clogged frequently from all the plant matter), and wouldn't mind snapping a few shots if my description is poor.

HTH,

justin

 

[fish_4_all]

If it is that simple then that is great. It can't hurt my levels, I wouldn't think anyway. I will let you know how well it works. Would be some good scientific data. Thanks 7, that could be the help my plants need if it works. And the bomb shell to get rid of my algae! How long should it take to see an increase in levels?

As for inorganic and organic, I haven't a clue. All I know is I test out at 20-40ppm NO3 and almost never have to add any. I guess there could be a ratio of inorganic to organic in the tank at the same time, I don't know. I guess the worst worry is if there is inorganic and organic levels and they could be about the same, that should explain why we need to keep the tested levels below 40ppm. Is scary to think that a tested level of 40ppm could actually be 80+ organic+inorganic.

 

[7Enigma]

Only a couple of hours to see a change in levels, but for the best accurate test you want to check the levels at the same time, ideally 24hours apart. That way you can be sure that the only thing factoring into the equation is the CO2 level (pH changes due to light, etc). Personally I'd check in the morning right before the lights come on. This will be your max CO2 level (and thus lowest pH reading). I'd check again before the lights go off as this should be your lowest CO2 level (and highest pH reading). It's nice to see exactly how much your pH fluctuates during a normal day.

Goodluck and let us know how it goes!

 

[newfound77951]

newfound77951, lets say someone adds 10ppm of organic NO3 into a typical, cycled tank with a healthy biofilter. What is the amount of time (ballpark figure) before it is converted to inorganic NO3? Will the result be 10ppm inorganic NO3, or is it not a 1:1 ratio?

Wow, I feel like I'm taking comps all over again....lemme give this a shot....the thing with organic nitrogen is that it isn;t just NO3, "organic N" can take many different forms (ie amino acids, proteins etc). Same thing for P. That's why they are so hard to test for, you have to actually digest the big organic molecules with some nasty stuff (potassium persulfate, a very strong oxidant, and boil it too....very scary) in order to break all the compounds down into smaller, inorganic molecules (like NO3 and NO2), which common nutrient analysis machines can measure. Essentially speeding up the natural decomposition process that the bacteria do. Then to determine organic N, you would take the amount of N from the digested sample, and subtract the amount of N measured from a "regular" dissolved (inorganic) N sample. Confusing, huh?? That means that we really don't have a good idea how much inorganic N you get when you add x amount of organic N, unless you know exactly what kind of organic N you're adding.

Off the top of my head I have no idea what the exact reaction times are. A good ballpark is a probably on the order of a few days, since when folks do a fishless cycle and add 1 ppm ammonia, it's converted to NO2 and NO3 by the next day, when the filter is cycled. Organic compunds take longer to break down than pure NH3 since they are large molecules. Some of them probably never get broken down at all, or only very slowly.

When we cycle a tank and test NH3/4 and then NO3, are we really waiting for organic ammonia to convert to inorganic ammonia, then organic to inorganic nitrIte, then organic to inorganic nitrAte? Or is the organic-inorganic thing only because nitrates are the last step of the biofilter?

The beneficial bacteria that we want in our tanks take inorganic NH3, convert it to NO2, then another bacteria converts that to NO3...all inorganic. It's most likely another whole set of bacteria that break down the organic compounds into the inorganic ones that we measure, and that the plants take up. My guess is that the organic to inorganic breakdown is slow enough that the biofilter can process any additional N and P faster than it is produced, so it never really becomes a problem. It is true that plants preferentially take up inorganic nutrients, for two likely reasons: 1) they are simpler to deal with (don't need to be broken down by the plant before use) and therefore more energetically efficient, and 2) they are more available. From my marine nutrient analysis work, when folks are studying eutrophication (the effects of the addition of nutrients), they almost exclusively focus on the inorganics....so there;s a lot of science out there that indicates that inorganics are the main thing we need to be worried about.

Hope this makes sense....ask more questions if it doesn't!

As far as my CO2 goes....honestly I don't know....my pH is around 6.5 and hardness around 6, which by the chart is really high CO2....consequently it's likely that I have another buffer in my water, and I haven't taken the time to go through the "additional buffer" CO2 calcs (my bad). My guess is it's fairly low, since I only have 2, 1 liter CO2 bottles, and an active diffuser on a high light 55. I supplement with Excel, and although I have had some major algae problems (learning curve on my part), right now my tank is very, very clear with almost no visible algae anywhere.

 

[czcz]

Extremely informative. Thank you.

 

[fish_4_all]

I second the informative statement. I can't say I undertsood all of it but still informative.

Where is the CO2 link to that calculator for extra buffers?

 

[newfound77951]

I can't say I undertsood all of it

Sorry about that...I did my best to translate science into English.....it is hard to do sometimes! Glad the info helped....I've been running seawater nutrient samples for work/school for the past 4 years, it's actually not my thesis work so I'm not at expert but I know a fair bit. I really wished I had my Chemical Oceanography book with me last night when I wrote that answer, though......