Sodium hydroxide concentration calculation to match current 3 part.

[vdubers]

Hi all hoping some of you math / chemistry gurus can help me get my head around this.

So I currently use the below product as part of an automated 3 part dosing system on the Xepta autobalance. I’m not actually sure what it is made up of since calcium is dosed separately?

I mix up 5 litres of the solution and at this concentration according to the packet 35ml will raise the dkh of 100l aquarium water by 1 dkh.

Now after reading around about Randy’s DIY solutions I’m inclined to try and replace this KH part with sodium hydroxide for the PH boost.

Can anyone help me work out how to mix a solution with the same concentration please?

As in how much sodium hydroxide powder would I need to add to 5l of RO total volume to get a solution where 35ml dosed to 100l of aquarium water will raise the dkh by 1.

If I can mix this up right I can just replace the KH container and the rest should run as it has been.

The reason I need it to be the same concentration is that the Xepta autobalance will dose calcium and magnesium with trace elements based off how much kh part is dosed. It’s been working well this way for the past 18 months with manual adjustments of the ratio against my manual testing once a month but I’d like to explore the Ph boosting effects of hydroxide.

Thank you for your help.

 

[KStatefan]

That looks like it is about half the strength of Randy's recipe.

Converted to 100 liters 18.86 ml to raise 100 liters 1 dKH

 

[DanyL]

1dKH in 100L would amount to 3 grams of Sodium Bicarbonate which would make it a 85.7g/L concentration solution.

1 mol of Sodium Bicarbonate equals to 84g/L
1 mol of NaOH equals to 40g/L

I somewhat doubt they actually do make a 85.7g/L, unless they aren’t using Sodium Bicarbonate, given that it isn’t soluble beyond the 84g/L in normal conditions.

But going based on the 85.7g/L, that would amount to 40.8g/L NaOH, or 204g for a 5 Liter solution.

 

[vdubers]

That looks like it is about half the strength of Randy's recipe.

Converted to 100 liters 18.86 ml to raise 100 liters 1 dKH

1dKH in 100L would amount to 3 grams of Sodium Bicarbonate which would make it a 85.7g/L concentration solution.

1 mol of Sodium Bicarbonate equals to 84g/L
1 mol of NaOH equals to 40g/L

I somewhat doubt they actually do make a 85.7g/L, unless they aren’t using Sodium Bicarbonate, given that it isn’t soluble beyond the 84g/L in normal conditions.

But going based on the 85.7g/L, that would amount to 40.8g/L NaOH, or 204g for a 5 Liter solution.

Thanks for the replies. I was still getting confused and played around with chat gpt and got the below result which seems to work out roughly the same as what you guys are saying?

“To make a 5-liter sodium hydroxide solution with the desired alkalinity concentration of 1,020 meq/L, you can scale the recipe proportionally.

Step 1: Determine the amount of sodium hydroxide

The original recipe uses 283 g NaOH in 7.04 liters to achieve the target concentration. For a 5-liter solution:


\text{Sodium Hydroxide Required} = \frac{283}{7.04} \times 5 \approx 201 \, \text{g}


Step 2: Final Recipe

• Weigh 201 g of sodium hydroxide (NaOH).
• Add it to fresh water while stirring (always add NaOH to water, not the other way around).
• Top up the solution to exactly 5 liters.

This will result in a 5-liter sodium hydroxide solution with the same 1,020 meq/L alkalinity concentration.”

 

[DanyL]

Yes, they all roughly equal to a 1 mol solution of NaOH.

 

[vdubers]

Yes, they all roughly equal to a 1 mol solution of NaOH.

Thanks gives me a good starting point. Could I in theory if the PH increase is too potent mix the two in the same container? Or does that depend on what is in the actual Xepta part?

 

[Randy Holmes-Farley]

Thanks gives me a good starting point. Could I in theory if the PH increase is too potent mix the two in the same container? Or does that depend on what is in the actual Xepta part?

Yes, one can mix alk parts of most systems.

A word of advice on ChatGPT; it is very frequently inaccurate in chemistry math.

 

[DanyL]

There’s no problem mixing both.
However, if the Xepta KH supplement is based on Sodium Bicarbonate, it’ll make a lot more sense to use Sodium Carbonate instead of NaOH in case the increase in PH will be too high.

 

[vdubers]

Yes, one can mix alk parts of most systems.

A word of advice on ChatGPT; it is very frequently inaccurate in chemistry math.

Thanks I agree I don’t trust chat gpt when it comes to reefing stuff in general I just used it to see if it came up with similar numbers and help my understanding of how.

 

[vdubers]

There’s no problem mixing both.
However, if the Xepta KH supplement is based on Sodium Bicarbonate, it’ll make a lot more sense to use Sodium Carbonate instead of NaOH in case the increase in PH will be too high.

Thanks what points you to use sodium carbonate instead? Is that as a precaution if the resulting PH increase is too much? I do want a PH boost but just thinking ahead if it turns out to be too high

 

[DanyL]

Thanks what points you to use sodium carbonate instead? Is that as a precaution if the resulting PH increase is too much? I do want a PH boost but just thinking ahead if it turns out to be too high

I don’t have any details about your system, nor do I know wether Xepta uses Sodium Bicarbonate, or Sodium Carbonate instead.
So I cannot make any assumptions wether it’ll be too much for your system or not.

However, NaOH is quite potent in terms of PH increase, and unlike kalk where you’re limited in quantity - here you basically supplementing your whole Alk up take with extremely high PH solution, which further increases its impact compared to other solutions.

So for most systems, NaOH would likely be too much, especially if the system has high Alk consumption.

My recommendation about using Carbonate was in place of mixing your current supplement together with NaOH simply because it’ll have the same exact result, just with less steps and far easier handling.

 

[vdubers]

I don’t have any details about your system, nor do I know wether Xepta uses Sodium Bicarbonate, or Sodium Carbonate instead.
So I cannot make any assumptions wether it’ll be too much for your system or not.

However, NaOH is quite potent in terms of PH increase, and unlike kalk where you’re limited in quantity - here you basically supplementing your whole Alk up take with extremely high PH solution, which further increases its impact compared to other solutions.

So for most systems, NaOH would likely be too much, especially if the system has high Alk consumption.

My recommendation about using Carbonate was in place of mixing your current supplement together with NaOH simply because it’ll have the same exact result, just with less steps and far easier handling.

Thanks for the details helps get my head around it. My current dose of the Xepta ranges between 150-200ml roughly a day to maintain my 9dkh alkalinity on my 650 litre tank. My PH during the winter months ranges from 7.9 low to 8.3 high the high isn’t for long though and is only achieved through a open window, skimmer line outside then into a co2 scrubber and with my algae scrubber light on. Will see if I can find some examples as to how much of a boost in ph the hydroxide might do in comparison.

Even if switching to hydroxide just maintained this PH level but let me not have the skimmer outside would be a bonus as sucking in the cold air during the winter can’t be good for my electric bills! I can feel a definite cold breeze around the tank