Po4

[fort384]

So my 29 gallon planted tank is coming along nicely, but thus far I have not observed much pearling with my plants. Other than that they appear healthy. However, I am getting a 0 reading every time I test for PO4, even with a fairly moderate fish load in the tank. Should I be dosing PO4 for plant growth, or wait to see what develops? The tank has been established for a little less than a month at this point.

FYI, I am running DIY CO2 at between 30-50 ppm, and running 2XHO T5 for 12 hrs a day. Been dosing Fe (maintaining around .1-.25 ppm Fe) and excel on a regular basis.

 

[Purrbox]

As long as your plants are growing well, not showing any signs of deficiency, and you're not having problems with algae you probably don't have anything to worry about.

What Phosphate test kit are you using? This can make a big difference in how accurate it is. Also you'll want to make sure that it isn't expired and that you are following the directions correctly.

It doesn't sound like you're dosing Nitates yet. What are your Nitrate levels?

 

[neilanh]

what kind of filtration are you using? In order for the plants to pearl, the water has to saturate with gas so that it doesn't absorb it anymore. If you have a lot of surface agitation allowing the water column to offgas, that will prevent this from happening.

 

[fort384]

My PO4 testkit is a "Salifert". It is not expired. My filter is a Topfin 30 hang off the back type with carbon filter bags. Nitrate levels are hanging around 20ppm, I am not dosing nitrate. I do have a little algae, but nothing I would call a problem at this point.

 

[Purrbox]

I just did a quick search on the brand of test kit you're using. From what I found it doesn't sound particularly sensitive to lower levels of phosphate. Since you aren't having to dose Nitrates, you probably don't need to dose Phosphates either. This is particularly true if you aren't having any issues with GSA. You'd probably need to look at dosing Potassium, before Nitrates and Phosphates.

 

[czcz]

With that much CO2 I'd add 1ppm PO4 and see what happens, for what its worth. I'll bet trims your N drops in a day or two and it becomes K, N, or P limited. But I also think dosing moderate light CO2 injected tanks is good.

 

[fort384]

Well, I took your advice. I bought the Flourish K, N, and P mixes today, dosed earlier, and just did a comprehensive water test. My kit is now showing about .03 PO4, and my Nitrates are now at about 30ppm. Is that about where I want to keep it? Also, is there a reliable test kit for K?

 

[czcz]

How much PO4 did you dose to start the day? I'd take that number and multiply it by like 3 and dose that amount every two days so the tank never bottoms out (and plan ahead for more plant mass). I would keep dosing Fe. But I know this is crazy to non EI folk (explained below -- from cruising the forum it does not appear there has been a strong EI advocate so please forgive me if one of us has already crossed your path )

I recall Travis talking about some K kit he liked, and know its in the archives here, but have not searched. (I have dosed tons of K with and without Ca and don't think it matters. Also keep in mind you're adding lots of K with Flourish Nitrogen, too.)

Anyway, there's lots of ways to do this, but I'm going to try to push you towards dosing more PO4 and K and dosing N despite your tank levels, which is really the Estimative Index, and I'll tell you why: now that you're injecting CO2 at very high amounts, you have an excess of the biggest chunk of stuff plants are made of. You also have an excess of Nitrogen, which is the second biggest element in plant mass. With the two of these things together, you have the majority of what makes the tissue of your plants.

Also as you know, high CO2 inhibits algae and, at your ranges, gives you a nice fat buffer.

So, you have two good things going for your plants, plus you have enough light to grow plants. The only saftey net you may be missing is high plant mass (which means more growing, which means more trimming, which means more nutrient export). So, just give the plants the rest and, watch, it all becomes way easier.

(Re limiting NO3 for fish saftey, because this is the point that most find confusing about EI. Let's say you have 20ppm organic NO3 from fish waste right now. Let's say you add a little less than 7ppm NO3 from KNO3 three times a week. That's about 40ppm. Let's say you do a 50% pwc at the end of the week. You'now have 20ppm. Let's say you add that 40ppm again. You now have 60ppm. Let's say you do a 50% water change to bring it to 30ppm.

Again add 40ppm and do a 50% water change. That's 35ppm.

Again, 40ppm and a 50% water change is 37.5ppm.

Etc. We'll approach 40ppm super slow. That's with 0% uptake from plants, which of course won't happen, because you have plenty of everything plants want. )

I don't think it really matters how much light we use if we have enough light to grow the plants we want and so this reads a lot like a high tech/high light tank post, by the way. I think with almost all plants more light just means different growth.

Sorry for long post but hope it helps. I mean it about the trims if your N doesn't drop within two days of dosing 1ppm P (and to hedge myself a little say 5ppm K), by the way

 

[mgamer20o0]

for PO4 you can always just buy fleet and save your self some money that way. also if your going to start adding ferts to your tank i would invest in the dry ferts. it will last you a long time. you can ever mix your own into liquid and make the same Flourish brand stuff for pennies.

 

[fort384]

The thing I don't like about EI is the 50% water change at the end of the week. I have extremely hard tap water with very high pH. Doing a 50% water change I think would be stressful to the inhabitants. It would also take longer to fill/treat that much water on a weekly basis. It is quicker to just test for macros, use a comprehensive fert for micros, and maintain a balance.

I have not seen a lot of advocating for EI on this site, but there are definitely a lot of advocates out there. Who here uses EI?

 

[mgamer20o0]

i do 50% wc or more on all my tanks weekly EI or not. i have ph 8 i forgot the hardness off hand but so cali is known for its high ph and hardness.

i use ei on my 120 planted high light co2 tank. again EI is just a stepping stone. mod it for your own need since all tanks are different. you can also make your own liquid thats the same as Flourish and do that. its all about finding what works for your self.

 

[czcz]

Thats fair. If you're uncomfortable with resets at all -- as you know, it doesn't really matter exactly when and how much water we change; with doses slightly above uptake its totally reasonable to change say 30% of water every couple of weeks or month. The point is to remove unmeasurables/TDS/DOC/salts/etc and "reset" (or come closer to baseline) on macros/micros -- dosing P and K for the relatively small ppms your tank needs to have all nutrients then trimming for export still applies. Once we inject CO2 at your doses risk/reward simply weighs heavily (like, overwhelmingly) to a comprehensive dosing cycle. So, fwiw, I would still suggest 1-2ppm PO4 doses and dumping in a bunch of K.

I've been unwet for a while and until recently have not kept up with AA outside of occasional glances. Back in the day I would say almost every high light tank on AA ran some deviation of EI, though some called it something different, and only very few people went the way of nutrient limited or target doses or really drifting to other methods. Instead we progressed to individual nutrients: what does tons of PO4 do? What does hardly any N do? What happens if we have confidence the majority of a forum has learned to dose up, then start looking at their lights? Rick is rocking R. wallichii when he used to worry about algae. Holy crap, Zezmo has sweet Eriocaulonae. This guy Glen has some weird thing about some Ammania sp... oh dang, nice tank. Good nerdy times.

I'm also of the opinion that any dosing method that is built around the idea of no limited nutrients and dosing up to make our lives easier is "EI", whether one uses test kits or not, by the way. But this may also be because Plantbrain was one of my gurus and in discussions with him it became clear to me he stopped caring about ppm and credit and all that a long time ago unless he was trying to prove some point: he's totally dosing blind (well, using known introduced doses [though everyone who EIs eventually eyeballs this], plants, fish, and years of experience and training as indicators) and if you corner him on that he'll tell you so. The idea is no 0s, thats it. But lots of folks have disagreed with me on the "almost all of it is EI, even when you use calibrated kits to limit the maximum threshold" thing.

Babble.

 

[fort384]

I appreciate your thoughts. Being new to planted tanks (and aquariums in general) I like the security blanket a test kit provides. I will keep your advice in mind as I continue to fumble through this. I still like the idea of doing 10-20% wc's weekly as it is quick and easy. I am going to pick up a K test kit and see where this leaves me with macros. Thanks again for sharing your knowledge and experience!

 

[czcz]

You're doing great: keep it up!

I would suggest skipping the K test, not to discourage your testing and targets plan (you should do this and whatever makes sense to you), but because you'll find difficulty finding anyone who thinks excess K matters. And those who feel excess K matters mean it in relation to Ca, and if you're dosing Ca you're either reconstituting RO or growing like an L. "Pantanal" or something. No one I am aware of claims excess K (say, under 100ppm) hurts fish, though logically how we introduce K may (salts).

Don't worry about K -- really. For every 10ppm NO3 you add from KNO3 (like Flourish Nitrogen) you add about 5ppm K. You can toss in another say 10 or 20ppm and likely won't have to care. Keep up with testing around N and P. Remember to occasionally test your kit against a known sample around your targets (say 5ppm, 10ppm and 20ppm NO3, 0.5ppm, 1ppm and 2ppm PO4) so you know what the kit is actually saying.

HTH

 

[fort384]

Ok- will skip the k test then. Thank you.

 

[czcz]

Hey. I just wanted to add Purrbox's advice and the sentiment that if its not broke don't fix it is smart and sound. I just think >30ppm CO2 tanks are automatically golden and you just need to nudge them a little to go from having plants in a tank with little-to-no nuissance algae to having a garden and being amazed by how cool plants are. (Like the great feeling that comes from inducing pearling that you want in this thread. I feel like a little kid when I see pearling.) I'll stop beating this horse now.

 

[fort384]

I understand and appreciate Purrbox's advice as well. However, I want to see the greenest possible plants, and see some real growth (some pearling wouldn't hurt either). Everything I have read points to CO2/light/fertilization to make that happen. I think I have the first two chunks of the equation - just need to get my arms around the last part as much as possible. Again, thank you for taking your time to advise me!