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The importance of a 1 point pH drop

sonicninja

Member
Joined
15 Dec 2013
Messages
307
Hi everyone,
I've had a planted tank for about a year now and have had a lot of issues getting the plants to stay alive and grow. I've finally got the hang of it after a few posts of these forums (thanks everyone).

I'm currently having success with easy species such as hygrophilia and staurogyne repens and have a good and steady routine with dosing ferts and injecting CO2. Ive also made a series of significant improvements on my tank to increase my chances of success but one bit still eludes me.

I've read a lot about trying to get a single point drop in pH before lights on. I'm currently injecting at a level that my fish are comfortable with but any higher the fish begin to show signs of stress. However despite pushing my injection rate as high as i can without upsetting the livestock I cant get near to the suggested drop. In fact even when I had no livestock i attempted the same thing and could only get close with a bubble rate of close to 7bps (hard to gauge when its that fast).

My surface agitation is at a minimum and the CO2 currently comes on 3 hrs before the lights, it seems like getting lower than 6.5pH is a struggle for me (my tank water is 7.0pH normally).

The CO2 is injected via an in-line atmoizer and then a spray bar running the length of the tank. The filter is an Eheim 3E 450 (1700lh) on a 65litre tank so even at half the stated output my flow is plenty and all the plants move visibly from the front to the back.

My KH is 6dH which means considering my pH is 7.0 before i even start injecting CO2 Im already at an ideal level (http://s171.photobucket.com/user/plantbrain/media/Aquatic plants/CO2_Graph_zps9c124ef0.gif.html).

Can someone explain this to me? Perhaps it could be my pH pen (cheapo ebay model) or alternatively its ability to read water with a high proportion of RO water. Very confused!!!

Any help would be great, should I continue to get a full point drop or give up and look elsewhere?

Cheers everyone!
 
Forget the kh/co2 table, that works if you use RO water, otherwise it is misleading. Focus on the PH drop, and I think you are on the right track. In order to be able to increase CO2 without stress fish, you need to increase surface agitation, without splashing, remember that Co2 and O2 are independent. What's your tank size?
 
Thanks fablau. The tank is an ADA 60P (60x30x36). I currently just have the spray bar which I could attempt to raise. Annoyingly they are made in a what which prevents it being lifted but i'll see if i can do it in a safe way this afternoon.
 
Seriously, I think the best way to get consistent surface agitation (and no surface film) is an Eheim Skim 350.

The 1 pH drop can't be taken as gospel because CO2/pH varies so much throughout an aquarium, and we most likely measure pH somewhere near the surface of the water (where CO2 levels are highest).

If the fish are unhappy due to too much CO2 I guess they go to the surface because (assuming you have decent agitation), O2 levels will also be the highest there.

Another reason that you need agitation is to be sure that the CO2 completely de-gasses (once injection stops), to a level in equilibrium with the air. This way you know that any pH drop is due to the CO2 you have added and that you are truly starting from 'zero'.

P
 
Okay, this is really helpful. I have a small 250lph powerhead that I could put in to increase the surface agitation but Id rather keep equipment in the tank down to a minimum. Is raising the spray bar a good place to start?
 
I have a stainless steel inlet tube with a built-in clear acrylic surface skimmer. Was expensive and they aren't on the market any more.

So I can only recommend the Eheim Skim 350 which I used before and now use on another smaller aquarium. It isn't too expensive and it gives consistent performance (you will have to clean the sponge each week though).

With a surface skimmer, the skimming part floats on the water and so it goes down as the water evaporates. With a powerhead or spraybar, the surface agitation is gonna increase as the water level falls.

P
 
good point, perhaps i'll look at the eheim as ive seen it fairly cheaply. So presumably I could run the spray bar where it sits naturally at about 3cm below the surface and a skimmer on the side to keep surface agitation up.
 
.......having said that I cant see how the skimmer would agitate the surface? Looking at a vide the water is sucked in gently at the top and expelled much lower down in the water column. Does it collect a mixture of water and oxygen at surface level?
 
Do you know that higher alkalinity (wrongly called "KH") does prevent pH drops much better then low alkalinity?
So if you have alkalinity of 6°dKH, and someone else has 1°dKH, then his pH can drop much easier then yours, as alkalinity work as a buffer against pH fluctuation.
 
i think it`s best to have the holes in the spray bar just under the surface.
 
The skimmer aerates the water well because the water falls down the hole at the top. I think it is here that the gas exchange happens as there is a high surface area to volume ratio.

P
 
A short clip to show you how the spray bar ripples the surface when the light and co2 are on, and then what I do during the night. No need to use any skimmer in my case. The spraybar is just 1.5 cm under the water level. This way I achieve a 1 ph drop with KH 10+, inline atomizer, 2 bps and a filter rated 10x the tank volume



Jordi
 


This is mine, I've raised it as much as I can and this is with the water as high as it would ever be.


Sent from my iPhone using Tapatalk
 
I agree, I'm amazed that you can can achieve a tank like that with 2bps. I think that's what I find difficult to get my head around, I understand that conditions and parameters differ tank to tank but it amazes me that you can create a tank as a lush as that with 2bps and i struggle despite good injection and circulation methods with a far higher rate. Also, my tank looks far smaller than yours, I dont understand why my tank is seemingly so inefficient.

For example, there is a chap on here who im sure you've come across. He also has an ADA 60P and the growth is simply stunning, however he doesn't seem to have had anywhere near the issues i've had with getting the CO2 to the plants and got amazing growth and health using an in tank glass diffuser and glass outflow pipes placed at one end of the tank. This isn't to downplay his achievements but quite the opposite, its just frustrating the amount of time and effort you can put in for often little in return.

Having said that im still chuffed with what i've accomplished. Ive learned a lot but its just that final piecing together of the puzzle that im looking for. It seems to allude me!
 
2 bps? I don't get it. I have KH 4 and I get a 1 pH drop with uncountable bubble counts! :confused:

P
Well... As you know bps is not an accurate indicator of the gas delivered. Your bubbles may be smaller, your diffusion device different, your timing, tank volume, etc. At the end it is a matter of effectiveness of your dissolution technique which includes lots of aspects.

This is IMO the most tricky part of high tech planted tanks. There is no magic recipe that can be transferred to other tanks. pH drop, flow rate and so on are just rule of thumbs but the fact is that each one has to fine tune all this for his/her tank.

Jordi
 
I agree, I'm amazed that you can can achieve a tank like that with 2bps. I think that's what I find difficult to get my head around, I understand that conditions and parameters differ tank to tank but it amazes me that you can create a tank as a lush as that with 2bps and i struggle despite good injection and circulation methods with a far higher rate. Also, my tank looks far smaller than yours, I dont understand why my tank is seemingly so inefficient.

For example, there is a chap on here who im sure you've come across. He also has an ADA 60P and the growth is simply stunning, however he doesn't seem to have had anywhere near the issues i've had with getting the CO2 to the plants and got amazing growth and health using an in tank glass diffuser and glass outflow pipes placed at one end of the tank. This isn't to downplay his achievements but quite the opposite, its just frustrating the amount of time and effort you can put in for often little in return.

Having said that im still chuffed with what i've accomplished. Ive learned a lot but its just that final piecing together of the puzzle that im looking for. It seems to allude me!
Well, it took me one year to find the sweet point and my tank is far from being good. I gave achieved to grow a good amount of plants but honestly not very difficult ones. Apart from pH drop other issues are important as you know. For example I haven't been able to reduce algae to the minimum with high lights (in 64 liters I have just 48w t5 20 cm above the water surface), I have no hardscape blocking my flow (in my journal I explain that this tank is 'just plants', a way of testing plant growth in the easiest conditions).... Once I will be able to do so it will be the time to play the aquascaper

Jordi
 
Fair enough. I suppose that each tank is very different and has its own issues to overcome. With this forum being absolutely crammed with members who have insanely good looking tanks its easy to be downbeat if you dont feel you own tank is up to much. I know im on the edge of this tank exploding, compared to what I had 4 months ago before the re-scape its fantastic but i know there's more to do.
 
As some have already said, each tank is set up differently and all the tests such as drop checkers, bubble rate, type of diffusers etc etc all factor in to getting the optimum levels for plant paradise and non toxic conditions for fish and shrimp. You seem to know what you need to do but it can hard to just get that balance right .... keep trying by upping one factor and seeing if there is any change and if not try the next factor and so on until you see which one makes the most difference and then try factor 2 and so on until you see that change and then you will have your own rule of thumb. It can be irritating seeing some people get it right straight away or soon after set up but that is just the way it goes.
 
thanks Brian.
Since upping my CO2 today (fractionally i should add) my fish are looking fairly sheepish. the corys usually play at the front of the tank but i havent seen them since upping the CO2. The otos are also looking pretty lethargic.
Im not concerned yet but everything has got a bit 'dozy'
 
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