Plant strategy, now and future?

[GlassWalker]

Hope this is the right place, as I have lots of related questions which seemed better to keep together than split across multiple sub-forums.

As mentioned in my intro thread, I've historically been more interested in fish with plants as a side thought, but want to step up a gear with plants now. Chances are I've picked up all the bad information on plants on other forums and do expect to be corrected. Be gentle with me!

A detailed description of my main tank is here. In short: 260L nominal capacity (will be bit less after displacement) 4ft bowfront tank. 42W LED lighting. No added CO2 or liquid carbon, estimated daytime CO2 about 5ppm. Low dosage of EI ferts (approx 1/3), weekly 25% water change. Originally filled with tap water, changing with remineralised RO to lower hardness and therefore pH in longer term. Tank has been set up for just under a month, but the contents were from existing tanks, other than some new plants I got since then.

Question 1: Is there anything I should do right now to optimise this tank? In particular, I've already browsed this forum and suspect I might be running high on light for a low tech tank. I have liquid carbon but stopped using it as I do keep vallis in all tanks now.

Question 2: I'm thinking of going CO2, both to aid plant growth and lower my pH some more (I have lower pH and/or soft water preferring fish). I have a local FE source lined up, and am looking at buying an existing used CO2 setup. Presumably once I do this, I'll need to go up to full EI dose, but there is no practical way I can do 50% weekly changes with my current RO production rate. At best, I could cut it with tap water but we're still in perhaps 35% change ball park. Is this going to be a big problem?

Question 3: I see tank flow being mentioned as important to get all the stuff around and mixed, but so far I haven't seen this quantified. Just how much flow are we looking at? I have spare circulation pumps from my marine tanks I could bring in if needed.

 

[James O]

Q1: what's your current photoperiod?
Q2: no idea 😕
Q3: 10x volume is a loose standard to aim for

 

[tam]

What's your tap water like? That will make a big difference when cutting it with RO, as to what you end up with. Some people do that routinely - mix it back with tap, rather than using powders to adjust.

 

[tim]

Q1, cut light intensity and duration unless you have no issues in which case you have hit the sweet spot 🙂
Q2 don't add co2 to adjust ph it won't benefit any part of your setup.
Q3. 10x flow is standard for high tech 2-5x is adequate for low tech.
If your tanks in a happy place stick with it, 50-80% water changes are a must sometimes with high tech tanks IMHO whether you want to carry them out or not will depend in the amount/types of algae you battle, your call 🙂

 

[GlassWalker]

Currently lights are on 10 hours a day. The only algae are diatoms but I'm not surprised since the tank is relatively new and they all seem to go through that phase. The only "problem" with my lights are that I've recycled spares from previous tanks. One is an 18W interpet 4ft x3 array, which is ok but looks pretty dim by itself. I added 2x 12W Aquabeams to perk it up a bit, but I don't want to run them by themselves as they have a strong shimmer effect. I think part of my problem is this is also my first time with a painted black background and I'm using black sand substrate too. It just looks so dark compared to other tanks with natural sand and stick on backgrounds (we were all noobs once!) I'll see if I can reach the timer at some point and drop it down to 8h perhaps.

Based on filter nominal rating I'm at 8.5x flow then (1200+1000lph, into 260L), although in practice I think the filter flows are a fair bit lower than that. I have a little circulation pump rated 1600lph I could easily put in if needed.

My tap water is pretty hard. In German degrees, I have KH around 10 and GH in 15-20 ball park. As a target, I'm looking to drop KH to perhaps 4 or so from current 6. As background, I had another 4ft tank that sprang a slow leak, so the livestock had to be temporarily housed in my smaller tanks which were then all massively overstocked. When I got this tank to replace it, I just set it up fast using tap and have been looking to bring it back down again since.

I think I'd struggle to produce more than 60L of RO for this tank a week and only managed 40L last week due to other activities. Cutting with tap for KH 4, that would result in about 100L, or about 35-40%. Note I also have many other tanks to do other than this one. Maybe this is an excuse to upgrade my RO unit to a faster one...

As further background, for my freshwater tanks my general goal is 25% weekly changes, perhaps a bit less or more depending on the tank volume relative to my bucket size as I think in buckets. Occasionally due to work travel, I may need to skip changes for a week. Wish freshwater was as easy as marine. There I only do one 25% change every couple months or so...

 

[ceg4048]

The OP should abandon the idea of RO and go back to using tap water. Neither fish nor plants care about pH, so this is wasted energy. The worst reason in the world for adding CO2 is to lower pH. That's just begging for trouble.

Additionally, even soft water originating fish do fine in hard water as long as it's kept clean. CO2 enriched plants produce a massive amount of organic pollution which makes the water hostile to both themselves and to fish. Focus therefore on keeping the tank immaculately clean and ignore soft water requirements. The best policy is to make life easier in terms of collecting RO by simply using tap and perhaps cutting it occasional with rain water (unless you live in a desert) and instead use that saved energy to perform massive weekly water changes, 50% or more.

Skipping a water changes occasionally is not really a big deal. If the tank is healthy then it is easily able to absorb a few hits to the routine. It's when the plants are unhealthy that the maintenance schedule becomes critical.

Learn to grow plants with the water that you have at hand FIRST.

Cheers,

 

[GlassWalker]

Perhaps I misstated the pH thing. My main goal of using RO was to lower hardness, which in turn has the effect of lowering pH. I know that adding CO2 would also have the effect of lowering pH (not hardness), but that wasn't the purpose of wanting to add it in the first place. Probably a bad habit which I'm not alone in, but low pH and soft water are often used interchangeably, where I do recognise they're not the same thing.

On the remineralised RO part, I have been using it for a long time so as far as I'm concerned, this is the long term stable condition of my freshwater tanks. I do want to closer replicate the fishes native water conditions than using tap would, even if they may be tolerant of harder water, and/or that captive bred fish may have diverged from their wild counterparts somewhat.

The limit is simply my RO unit is a relatively slow one and effectively produces about 8L/h which I need to manually manage to prevent overflows in the collecting container (an auto stop mechanism is on my to do list). I have got the routine of using it pretty sorted, moving it to a mixing bucket (choice of 20L or 60L) where I mineralise and temperature match it, before pumping it in the tank. No heavy lifting required. If it comes to requiring 50% weekly changes, I can look at getting a bigger RO unit as I know the one I have is tightly integrated and not upgradable.

 

[Sacha]

Hello you 🙂

Can you not get a pump for your RO unit? Used to take me about 7 hours to produce 50 litres of RO. Now it takes just over 2.

 

[James O]

I'd guess that the majority of fish spend their pre purchased lives in anything like ideal water pH, hardness (just part of large combined systems) Many will have spent their entire lives in unnatural (as compared to origin) water systems.

It would be interesting to test the water (yourself) from the tank you wish to buy fish from. (I think I read a change of 1 pH or more in a short period was bad for fish)

 

[GlassWalker]

The RO unit is pumped. 8l/h is roughly 50 USgal/day which is its rating.

I know captive bred fish could well be kept in different water than their natural habitat, but it is practically impossible for me to trace back to original source. I can only assume undoing nature's original work could take a while, so tending towards their original conditions is better than doing nothing at all. If it wasn't for mixed species I'd consider doing a biotope tank. LFS water is similar to mine, and I do acclimate them on acquisition.