When sending transfers from your Coins.ph wallet, at the moment you cannot set your own gas limit. However, It's currently set to allow transactions to other Ethereum wallets only. Please make sure that the receiving address can accept transactions done via smart contract.
You can check this link to know more about the types of Ethereum wallet you can send to.
On the other hand, when receiving ETH from external platforms to your Coins.ph wallet, please make sure to set a minimum of 70,000 gas limit to ensure a successful ETH transfer.
