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Nutrients in General and P in Particular

1683 Views 6 Replies 3 Participants Last post by  plantbrain
Ok, this is my first post on this forum. I've been a member of others for quite some time. I just read a long, involved thread in this section regarding the dosing/limiting of P as part of the dosing regimen.
I have 5 tanks: a 5, 10, 40, and two 55s. The first three are beautiful with minimal amount of algae. The 55s are a pain in the ***!!
I'm dosing all at: N=10ppm, P 1.0ppm, K= 15-20ppm. Dosed at water change once a week and checked to maintain at mid-week(except K which only is dosed at water change).
Traces(Plantex+B) are dosed as follows at water change: 12mls. for the 40 and 55s, and at midweek: 8mls. The 10 gets 5mls. at water change and 5mls. at mid week. The 5 gets 3mls. and 3mls. at mid week.
The small tanks run from 3watts/gal. for the 40(clean as a whistle), 3watts/gal. for the 10(beautiful), just under 4watts/gal. for the 5(a work of art). One 55 runs 2watts/gal.(CF) and a constant battle to maintain and the other 55 runs 3watts/gal.(NO) and is even more trouble to maintain. All tanks carry a light fish load which are fed sparingly.
All tanks are injected at 30ppm CO2 consistently.
Plant loads in all tanks run from heavy to jungle-like. The larger the tank the slightly less plant mass, but all are heavily planted.
The algae is the 'glass type' algae which seems worst on the Vallisneria, and of course on the Anubia. Also, I had a bout with BBA which is pretty much licked with the addition of SAEs and scrupulous cleaning/pruning.
Even with the addition of hordes of Otos and now Ancistrus Plecos, I can't seem to get rid of that dark, green crud.
I've been into planted tanks for a long time, but am wondering if there's just one little thing that I'm missing here.
Any feedback would be appreciated.

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I would not trust the N test kit. If the P is dropping, you likely have enough NO3.
Plants will take up some PO4 even at low NO3, but not for long.

Just keep adding KNO3, traces and the CO2. I suggested some other things like better current and mixing etc. Try those also. Mixing becomes harder in larger tanks.

You have only a fewe variables to monkey with.


KNO3-generally do not trust your cheap kits
Maybe some GH builder, SeaChem EQ etc

I have not been fond of CMS, I'll alternate days that I use it with Flourish.
I like TMG a lot also.
Might give those a try and give it 3-4 weeks to see.

Other things are maintenance routines.

But the basic notion is still not allowing the plants to run out of any nutrient. So adding more than what you suspect with test kits is often warranted and should not hurt the tank(you already have some issues but as long as CO2 is good, these should not harm anything).
So adding a little more will tell you if that is the correct path or not.
Note the plant's health, nothing else like algae etc.

Tom Barr
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Thanks Tom,
As I mentioned in the e-mail, the tanks are sucking up the P so I believe my test kit for N is somewhat accurate @approx. 15-18ppm.
If it shows a drop down to 10ppm I will dose more.
I also increased the Traces as I think I was way under-dosing the 55s previously.

Again, any feedback/impressions are appreciated.


I miss your question. If you are able to get good results in one tank you should be able to get good results in any tank. Why do the 55s stand out? Certainly they take a little longer to observe and trim. I have always done best with the tanks I look at most often. Other than volume what is different about how you take care of your tanks? Are the 55s outa sight and outa mind while the small tanks on your kitchen table and always in veiw?
No, I think my short-sighted dosing with regard to Traces has been the difference. Actually, I spend more time working on the larger tanks than the little ones. They seem to 'take care of themselves'. Now I realize that they were getting more adequate and better balanced nutrients. I will work to correct this.
I'm a little embarrassed that I didn't pick up on that myself, but that's what 'folks' like Tom are around to show.
As far as I can see, the tanks are proportionally very close in many areas.
The difference has been in the dosing.
I answer many questions from newbies that I sometimes have felt the answers to were obvious and just common sense. I'm not going to look at it that way in the future.

A question for Tom or anyone who might know the answer to it.
In his response above, among other things, he suggests the use of SeaChem Equilibrium.
I have a gH level of 4dH and a kH of 3.5. I also dose Mg as a regular part of my dosing regimen. With that in mind do you still think the addition of EQ is necessary, and if so, why?

You are ending up taking your own advice!
That's a milestone.
You are now an experienced plantie.

I hate that when I have to take my own advice!
I end up in an arguement I cannot win.

Tom Barr
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