Advice on pH levels for a planted tank

[iamthedruman]

Hi everyone,

I've been lurking for quite some time and I'd really appreciate some advice. I have a 39G planted tank with a mishmash of plants (amazon sword, Java Windalova + others (I think...), etc.) and fish (2 angels, 3 platys, 4 swordtails, 10 Zebra danios, 8 Neon tetras, and a bristlenose pleco).

My equipment is a Eheim 2213 filter with a PC 96 watt light. The tank has been running for approximately 7 months (since March) but was moved in August.

From Sept to last week (Nov 17) I was running six hours of light (7 am to 8 am then 5 pm to 10 pm). I've since bumped that up to eight in a single time block (1 pm to 9 pm)

Last week I finally got around to purchasing a test kit (Aquarium Pharmaceuticals Freshwater Master Test Kit & GH/KH Test).

My first test measured pH at 6.6 with Ammonia, Nitrite & Nitrate all at 0. My second test (today) measured pH at 6.4 with Ammonia, Nitrite & Nitrate at 0. KH measured 2 (^odKH) at GH measured 6 (^odGH). Temperature is a rock-steady 78.

My problem is the plants, they're all looking a little ragged (holes, turning brown, poor growth, etc.) I'm thinking (using my very limited knowledge) that the Carbonate hardness is quite low which is causing the pH fluctuations but I'm at a loss as to how I should try to fix this. Should I be considering something like API's Proper pH 7.0? Also, from what I understand raising the pH will decrease the available CO₂ and I am going to set up a homebrew CO2 reactor...

Any advice would be greatly appreciated!

iamthedruman

PS: Attached is a photo of the tank from last week...


[attachment deleted by admin]

[dan2x38]

Your readings are OK KH is a touch low but it could be 3 if it off a bit. Also nitrate (NO3) should not be zero? I do not think the issue is KH or pH. How old is the tank? It is likely a lack of nutrients & shortage of CO2. You can suppliment for CO2 with Seachem Excel but if you have Vals it will damage them. Holes in the leaves can be a shortage of nutirents. Also goldfish, to many snails, & certain other fish can damage plants. Having some Seachem Flourish will help a lot. Be careful add a little at a time to see how things go you do not want to start an algae bloom.

[BigDaddy]

Raising or lowering pH has no effect on available CO2.  Injecting CO2 or outgasing it does.
 
Holes in older leaves or older leaves dying off is a sign of a nitrogen deffeciency and/or a potassium deffeciency.

What sort of fertilizer's do you use?

Don't worry about adjusting the pH or the kH.  Your plants will do just fine at those levels.  What you need to worry about is giving them the light and nutrients they need to grow.

[iamthedruman]

What sort of fertilizer's do you use?

I have a trio of Seachem Flourish: Organic Carbon, Comprehensive Supplement, and Iron. Though in all honesty, I have been very religious about adding them to the tank. Do you have any recommendations for how much/when I should be adding?

Also, with the amount of light I'm throwing at the plants, should I be considering additional CO₂ from a reactor?

Thanks for the help!

[charlie]

I have a trio of Seachem Flourish: Organic Carbon, Comprehensive Supplement, and Iron. Though in all honesty, I have been very religious about adding them to the tank. Do you have any recommendations for how much/when I should be adding?

Also, with the amount of light I'm throwing at the plants, should I be considering additional CO₂ from a reactor?

Thanks for the help!

Hello, the trio that you are doing takes care of the mico nutrients & carbon, you need to add some macro nutrients ( which would explain the problems you are having), by macro nutrients , i mean Nitrate , a bit of phosphates & Potassium, you can do it with the seachem line , it is not the cheapest choice , but one that would work with your tank.You can follow the directions on the individual bottles & get decent results.

They are cheaper alternatives of adding nutrients , but i would suggest sticking with the Seachem line for now.

Regards

[babblefish1960]

From Sept to last week (Nov 17) I was running six hours of light (7 am to 8 am then 5 pm to 10 pm). I've since bumped that up to eight in a single time block (1 pm to 9 pm)

My problem is the plants, they're all looking a little ragged (holes, turning brown, poor growth, etc.)

You have received some good indications and advice here on the basics of macro and micro nutrients, however, there is one nutrient that I would like to point out that is indeed in very short supply.  Your lights.  Without making you feel bad, your plants should be receiving no less and no more than 12 hours of light each day, in one solid continuous block.  Otherwise, they will starve, they need light to survive.

Hopefully you can see the relationship between your current light schedule and the conditions of the plants, they're dying of light shortage.  Put your lights on a timer and see how much that helps to actually give them a proper exposure of 12 hours every day.

[iamthedruman]

Without making you feel bad, your plants should be receiving no less and no more than 12 hours of light each day, in one solid continuous block.  Otherwise, they will starve, they need light to survive.

Nope. Not feeling bad at all! I'm here to learn and the only way to do that is to get advice and unlearn bad habits!

I've just adjusted my timer accordingly... 

[kennyman]

One of the things to concider when determining where to set your Ph is the types of plants you want to keep. Based on information in books like "Encyclopedia Of Aquarium Plants" by Peter Hiscock and Diana Walstad's "ElNatural system" It is easier to keep softwater plants in hardwater than hardwater plants in soft water because the hardwater plants are adapted to obtain carbon from other sources than co2. And they also pickup nutrients differently based on availability of other elements in the water. The Softwater plants can still do well in hardwater by making carbon more available to them with co2 or other additives.

So with respect to Ph, higher levels of general hardness tend to accompany higher levels of PH due to the relationship between calcium salts, magnesium salts and carbonate hardness.

It is one of the foundations of the natural approach to aquarium management. Not with respect to design but management, That a hardwater aquarium is easier to maintain without addition of co2 if stocked with hardwater plants because of the higher levels of nutrients existing in hardwater.

At least thats the way I have been going at it since I have very hard water and needed to find a way to deal with it other than a RO system for aquarium water.

[fischkopp]

I agree with what has been said before. The slow and vestigial growth of your plants is a combination of macro nutrients deficiency (hence no measureable NO3), a lack of available CO2 and short light time.

Your setup with fluorite based substrate and about 3W/gal light intensity provides ideal proconditions to turn your tank into an aquatic eden.

CO2 supplement is a must for it in my opinion and you should consider to setup a DIY setup very soon. There is a lot of information about this on this site and in the web, just google a bit This will lower the pH, but this is really not a bad thing at all as most aquatic plants like it more acidic anyway.

Follow the advice and add more macro nutrients like N, P and K. But do it wisely as you don't want to trigger any algae growth. Many people like do use the EI (estimate index) dosing method as it is easy to use and does not require a whole lot of monitoring. Look here for more info about dosing via EI. And here for some basics

8 hours of illumination are the absolute minimum. Most of the plants you have are tropical hence 12 hours light should be used. Common suggests actually range from 10-12h a day taking into account that there is no full sun in the tropes for the whole day. I prefer 6 hours on - 4 hours off - 6 hours on schedule. The advantages of this is that the break helps to build up CO2 and some macros like N. It also said that it helps to control algae - but there are many pros and cons on this. I like the break to extend the time in the evening, I am usually not home around noon anyway

Good luck and keep us posted with the development of your aquatic garden

edit:
Corrected some wrong comments about KH. I noticed an increase of the KH after injecting CO2 but this is cleary caused by carbonate in my gravel.

Also they siesta on my tank serves more the purpose that the lights are long enough for me to enjoy it. On the other hand, I dont really have "properly setup" CO2 systems as mine are mostly DIY. But your are right, Siesta is no must at all.

[BigDaddy]

Correction fischkopp... injecting CO2 has no impact on kH levels.  It will drop the pH, but kH remains a constant unless you have calciferous material in the tank that the CO2 can dissolve into some kind of carbonate.

With a properly setup CO2 system, you should not need a "siesta" during the photoperiod.  Even with DIY CO2, it is entirely possible to maintain levels above 15ppm for the entire photoperiod.  I know.  I've done it. 

[charlie]

Hi everyone,

I've been lurking for quite some time and I'd really appreciate some advice. I have a 39G planted tank with a mishmash of plants (amazon sword, Java Windalova + others (I think...), etc.) and fish (2 angels, 3 platys, 4 swordtails, 10 Zebra danios, 8 Neon tetras, and a bristlenose pleco).

My equipment is a Eheim 2213 filter with a PC 96 watt light. The tank has been running for approximately 7 months (since March) but was moved in August.
From Sept to last week (Nov 17) I was running six hours of light (7 am to 8 am then 5 pm to 10 pm). I've since bumped that up to eight in a single time block (1 pm to 9 pm)

Last week I finally got around to purchasing a test kit (Aquarium Pharmaceuticals Freshwater Master Test Kit & GH/KH Test).

My first test measured pH at 6.6 with Ammonia, Nitrite & Nitrate all at 0. My second test (today) measured pH at 6.4 with Ammonia, Nitrite & Nitrate at 0. KH measured 2 (^odKH) at GH measured 6 (^odGH). Temperature is a rock-steady 78.

My problem is the plants, they're all looking a little ragged (holes, turning brown, poor growth, etc.) I'm thinking (using my very limited knowledge) that the Carbonate hardness is quite low which is causing the pH fluctuations but I'm at a loss as to how I should try to fix this. Should I be considering something like API's Proper pH 7.0? Also, from what I understand raising the pH will decrease the available CO₂ and I am going to set up a homebrew CO2 reactor...

Any advice would be greatly appreciated!

iamthedruman

PS: Attached is a photo of the tank from last week...

Hi there in the 7 mths your tank was running prior to moving , what was your photo period & how was the plants doing? , how long has it been since you started having growth problems with the plants?.

[Glouglou]

Ph in a planted tank should be around 6.5 to 6.8 because this is the range where all nutrients became the most available for plants.

This is for bigdaddy

Correction fischkopp... injecting CO2 has no impact on kH levels.  It will drop the pH, but kH remains a constant unless you have calciferous material in the tank that the CO2 can dissolve into some kind of carbonate.

Any acid, in this case carbonic acid will use some carbonate buffering capacity, lowering this buffering capacity.

Alkalinity is the capacity of a system to neutralize acid. How much acid can be added to a system before the pH of the solution is brought down to a certain level? The alkalinity of a natural water source is, for the most part, defined by the carbonate system. The carbonate system is the main group of molecules that determine how well a natural water source can "buffer" the addition of acid without the pH dropping rapidly. The molecules of the carbonate system that largely attribute to this ability to buffer large drops in pH are HCO3-, CO32-, and OH-. These molecules are bases and when H+ (acid) is added to the water source, the H+ ions will chemically bond with the bases. For example:

OH- + H+ —-> H2O;
CO32- + H+ —-> HCO3-;
HCO3- + H+ —-> H2CO3

it is shown here how the H+ ions chemically bond with the carbonate minerals. When the only carbonate mineral in solution is H2CO3, all the alkalinity has been used up since there are no carbonate molecules left for the H+ ions to chemically bond with.

[BigDaddy]

Very true.  However, very little of the CO2 we dissolve into our freshwater systems converts into carbonic acid.  The greater majority of it remains as CO2 molecules.

CO2 being dissolved into freshwater systems at levels that are still safe for livestock are very weak acids and have very little impact on the carbonate/bicarbonate system.

[Glouglou]

You right Bigdaddy about the amount of carbonic acid coming from the dissolution in water of CO2.
I was suprise that only 1% of the CO2 become carbonic acid, but the breakdown of this same carbonic acid release H+ ions.
Look at this.
http://scifun.chem.wisc.edu/chemweek/CO2/CO2.html

Carbon dioxide is released into our atmosphere when carbon-containing fossil fuels such as oil, natural gas, and coal are burned in air. As a result of the tremendous world-wide consumption of such fossil fuels, the amount of CO2 in the atmosphere has increased over the past century, now rising at a rate of about 1 ppm per year. Major changes in global climate could result from a continued increase in CO2 concentration.
In addition to being a component of the atmosphere, carbon dioxide also dissolves in the water of the oceans. At room temperature, the solubility of carbon dioxide is about 90 cm3 of CO2 per 100 mL of water. In aqueous solution, carbon dioxide exists in many forms. First, it simply dissolves.

CO2(g)  CO2(aq)

Then, an equilibrium is established between the dissolved CO2 and H2CO3, carbonic acid.

CO2(aq) + H2O(l)   H2CO3(aq)

Only about 1% of the dissolved CO2 exists as H2CO3. Carbonic acid is a weak acid which dissociates in two steps.

H2CO3      H+ + HCO3¯   Ka1 = 4.2 × 10¯7
HCO3¯      H+ + CO32¯   Ka2 = 4.8 × 10¯11

[Glouglou]

6.5 to 6.8 give you the range where the uptake of all nutrients ( Micro/Macro) are at is peak.