Balance Sheet vs Account Balance – mismatch (foreign currency). How to correct?

Balance Sheet vs Account Balance – mismatch (foreign currency). How to correct?

Hello, 

My base currency is USD. I also have a bank account in GBP. 
For this GBP account, I have:
- Opening balance = 0
- Then some incoming and outgoing transactions (let's imagine +100 then -100, many times on different days throughout the year)
- Closing balance = 0 

However, in the balance sheet, I have a balance of -10 GBP (imaginary number).

I assume the problem is with forex fluctuations. However, I want to show in the balance sheet 0, because by the end of the period, the real amount this account has is 0. 


What I have tried? I tried to create a manual journal entry:
GBP Account: Credit 10
Exchange Gain or Loss: Debit 10.

Now, the balance sheet shows 0 (as I wanted).
However, the problem now is that I have an account balance of -10 (in the Banking section of Zoho books).

I need somehow to adjust the balance sheet without affecting the actual balance of the GBP account. 

Could you please advise, on how to achieve this? 

I would greatly appreciate your support, 
Thanks, 
Ivan